Tag: MAKEPOINT()

Datafam Europe Live: London’s Top Attractions

Donna Coles1 Comment

This week’s #WOW2024 challenge was run live at the #Datafam Europe event in London and was a combo with the #PreppinData crew. If you want to have a go at shaping the data required for this challenge yourself, then check out the PreppinData challenge here. Otherwise, you can use the data provided in the excel workbook from the link in the #WOW2024 challenge (I’m building based on this).

Modelling the data

There are 3 data sources for this challenge which we need to relate together. We have

  • Attraction Locations – a list of attractions in London with their lat and long coordinates
  • Tube Locations – a list of tube stations in London with their lat & long coordinates
  • Attraction Footfall – a list of attractions with their annual footfall

Connect to the Excel file and add Attraction Locations to the canvas. Then add Tube Locations and then create a relationship calculation of 1=1 to essentially map every attraction to every tube station.

Then add Attraction Footfall to the canvas and relate it to Attraction Locations by setting Attraction Name = Attraction

Finally, in the viz we have to understand the distance between a selected attraction (the start point) and other attractions (the end point), so we need to have an additional instance of Attraction Locations to be able to generate the information we will need between the start and end. So add another instance of Attraction Locations and set the relationship as Attraction Name <> Attraction Name

To make things a bit easier for reference purposes, rename Attraction Locations to Selected Attraction and Attraction Locations1 to Other Attractions (just right click on the data connection in the canvas to do this).

Building the Footfall Bar Chart

On a new sheet add Attraction Name (from Selected Attraction) to Rows and add 5 Year Avg Footfall to Columns. Change this from SUM to AVG (as the data consists of multiple rows per year and this value is the same for each row associated to an attraction). Sort the chart descending.

Click on the 2 nulls indicator and select to filter the data which will remove the bottom two rows and automatically add 5 Year Avg Footfall to the Filter shelf.

Manually increase the width of each row. Set the format of the 5 Year Avg Footfall to be in millions (M) to 2dp, and then show mark labels and align middle left.

Create a parameter to capture the selected attraction

pSelectedAttraction

string parameter defaulted to St Paul’s Cathedral

show the parameter on the screen.

We need to identify which attraction has been selected, so create

Is Selected Attraction

[Attraction Name]=[pSelectedAttraction]

and then add this to the Colour shelf. Adjust the colours accordingly and set an orange border. Then add Attraction Rank to Rows. Set it to be a discrete dimension (blue pill) and move it to be in front of Attraction Name.

Set the font of the row labels to be navy, hide the row label names (hide field labels for rows), hide the axis (uncheck show header), don’t show tooltips, and remove all row/column dividers, gridlines and zero/axis lines. Set the background of the worksheet to be None (ie transparent). Update the title of the sheet and then name the sheet Footfall or similar.

Building the map

We’re going to use map layers for this, and will build 4 layers

  • the selected attraction
  • the other attractions
  • the tube stations
  • the buffer circle

When using map layers we want to work with spatial data, so we’ll start by creating a point for the selected attraction

Selected Attraction Point

MAKEPOINT([Attraction Latitude], [Attraction Longitude])

Double click on this and it will automatically generate a map. Add Is Selected Attraction to the Filter shelf and set to True so only 1 mark should display, Add Attraction Name to Detail. Show the pSelectedAttraction parameter. Change the mark type to shape and select a filled star. Set the Colour of the shape to navy and add an orange halo. Update the Tooltip.

For the buffer, we need another parameter

pDistance(miles)

float parameter defaulted to 1 that ranges from 0.5 to 2 with a step size of 0.5

Then create

Buffer Attraction (x miles)

BUFFER([Selected Attraction Point], [pDistance(miles)],’mi’)

And drag this onto the canvas and drop when the Add Marks Layer option appears

This will create a new marks layer, which we can rename to Buffer. Reduce the opacity of the colour to 0%. Move the marks layer so it is at the bottom (below the other marks card) , and set the disable selection option so when you move the cursor over the map the buffer circle does not highlight.

Adjust the background layers of the map so only the Postcode Boundaries are visible.

To add the tube stations, we first need to create

Tube Station Point

MAKEPOINT([Station Latitude],[Station Longitude])

Then drag this onto the canvas to create a new marks layer. Add Station to the Detail shelf of this new marks card, and move the marks card so it is below the Selected Attraction marks card.

We don’t want all the stations to display. We just need to show those up to 1.5x the buffer distance, so we need

Distance to Tube Station

DISTANCE([Selected Attraction Point], [Tube Station Point], ‘mi’)

format to a number with 2 dp and then create

Tube Station Within Range

[Distance to Tube Station]<= 1.5 * [pDistance(miles)]

Add this to the Filter shelf and set to True.

We want the size of the displayed stations to differ depending on whether they’re inside the buffer or not, so create

Tube Station Within Buffer

[Distance to Tube Station] <= [pDistance(miles)]

and add this to Size. Change the mark type to circle, then adjust the size as required. Change the colour to orange and add a white border. Add Distance to Tube Station to Tooltip and update. You may want to adjust the size of the shape on the Selected Attraction marks card too, so it’s bigger than the tube stations.

The stations need to be labelled based on the closest x number of stations that are within the buffer. For this we need a parameter

pTop

integer parameter defaulted to 5 that ranges from 5 to 20 with a step size of 1.

We need to rank the stations based on the distance, so create

Station Rank

RANK(SUM([Distance to Tube Station]), ‘asc’)

We’re also going to label the stations with a letter based on their rank

Rank Stations as Letters

CHAR([Station Rank] + 64)

but we only want to show labels for the ‘top’ ranked stations, so create

Label Stations

IF MIN([Tube Station Within Buffer]) AND [Station Rank]<=[pTop] THEN [Rank Stations as Letters] END

and add this to the Label shelf. Adjust the table calculation settings, so the calculation is computing by both Station and Tube Station Within Buffer.

Set the labels to be aligned middle centre, and allow labels to overlap other marks. If things are working as expected, then if you increase the buffer distance to 1.5 miles and the pTop parameter to 20, you should see that not all stations within the buffer circle are labelled

To add the other attractions, we need to create

Other Attraction Point

MAKEPOINT([Attraction Latitude (Attraction Locations1)],[Attraction Longitude (Attraction Locations1)])

and drag this onto the canvas to Add a marks layer. Move this layer so it is beneath the Selected Attraction marks card, and add Attraction Name (from the Other Attractions) section to Detail

Once again, we want to limit what attractions display, so need

Distance to Other Attraction

DISTANCE([Selected Attraction Point], [Other Attraction Point], ‘mi’)

and then

Other Attraction Within Range

[Distance to Other Attraction]<= 1.5 * [pDistance(miles)]

and add this to the Filter shelf and set to True.

Add Distance to Other Attraction to the Tooltip shelf and update. Change the mark type to shape. The shape needs to differ whether it’s within the top x closest attractions that’s inside the buffer or not. So we need

Rank Other Attractions

RANK(SUM([Distance to Other Attraction]), ‘asc’)

and then

Top X Attraction in Buffer

IF [Rank Other Attractions] <= [pTop] AND MIN([Other Attraction within Buffer]) THEN MIN([Attraction Name (Attraction Locations1)])
ELSE ‘Not Top X’
END

Add this to the Shape shelf. Set the table calculation so it is computing explicitly by both Attraction Name and Other Attraction Within Buffer. Setting the specific shape for each of the named attractions that could show is fiddly, so I just chose to leave as per the default values listed. The only shape I explicitly set was the Not Top X which I set to a filled circle. I set the colour of the shapes to dark grey and added a halo of the same colour to make the shape more prominent. The shapes also need to differ in size based on whether they are in the buffer or not, so need

Other Attraction Within Buffer

[Distance to Other Attraction] <= [pDistance(miles)]

Add to the Size shelf and then adjust sizes to suit.

Set the background of the worksheet to None, remove all row/column dividers and name the sheet Map or similar. Finally remove all the Map Options (Map > Map Options > uncheck all selections) to prevent to toolbar from displaying on hover. Test the map functionality by changing the various parameters and entering a new starting location.

Note – in subsequent testing I found that for some attractions where there were either no tube stations or other attractions within the range, the map would disappear. If I get time I’m going to try to work on a solution for this, but I’ll leave as is for now (Lorna’s published solution has the same issue).

Building the Tube Station Rank Bar

On a new sheet add Station to Rows and Distance to Tube Station to Columns. Add Is Selected Attraction to Filter and set to True. Sort the chart ascending, so closet is listed first.

We only want to display the stations that are within the buffer, so add Tube Station Within Buffer to Filter and set to True.

We also want to restrict this list to just those that are the closest ‘x’ to the attraction based on the pTop parameter. Add Station to the Filter shelf and on the General tab, select Use all and then select the Top tab and add the condition to display the bottom pTop by Distance to Tube Station.

However, this doesn’t quite show the correct results, as the Top n filtering has been applied BEFORE the other filters on the shelf. To resolve this we need to add Is Selected Attraction and Tube Station Within Buffer to context (right click each pill on the filter shelf).

Add Station and Distance to Tube Station to the Label shelf, and adjust the label to display the text as required and align middle left. Change the mark type to bar and manually widen the width of each row so the labels are readable. Adjust the colour of the bars.

For the circle labels, we need a ‘fake’ axis – double click into Columns and manually type MIN(-0.05). Move the pill that is created to be in front of the Distance to Tube Station pill.

Change the mark type of the MIN(-0.05) pill to circle and remove the fields from the Label shelf. Add Rank Stations as Letters to the Label shelf instead and adjust the table calculation so it is explicitly computing by Station. Format the label and align middle centre.

Make the chart dual axis and synchronise the axis. Remove Measure Names from the All marks card.

Don’t show the Tooltip, remove all row/column dividers, hide the axis and the Station column. Hide all gridlines, axis lines, zero lines. Format the background of the workbook to be None (ie transparent).

Update the title of the sheet referencing the parameters as required, and name the sheet Tube Station Rank Bar or similar.

Building the Tube Station Rank Bar

On a new sheet add Attraction Name (from the Other Attractions data set) to Rows and Distance to Other Attraction to Columns. Add Is Selected Attraction to Filter and set to True. Sort the chart ascending, so closet is listed first.

We only want to display the other attractions that are within the buffer, so add Other Attraction Within Buffer to Filter and set to True.

We also want to restrict this list to just those that are the closest ‘x’ to the attraction based on the pTop parameter. Add Attraction Name to the Filter shelf, on the General tab, select Use all and then select the Top tab and add the condition to display the bottom pTop by Distance to Other Attraction.

Add Is Selected Attraction and Other Attraction Within Range to context.

Add Attraction Name (from the Other Attractions data set) and Distance to Other Attraction to the Label shelf, and adjust the label to display the text as required and align middle left. Change the mark type to bar and manually widen the width of each row so the labels are readable. Adjust the colour of the bars.

Double click into Columns and manually type MIN(-0.1). Move the pill that is created to be in front of the Distance to Other Attraction pill.

Change the mark type of the MIN(-0.1) pill to shape and remove the fields from the Label shelf. Add Attraction Name to the Shape shelf. Set the colour of the shape. Edit the shape for each Attraction so it matches the shapes assigned to the attractions on the Map sheet. Unfortunately, this is a bit fiddly and just a case of trial and error which involves changing the parameters to try to ensure all the options are presented at least once of each of the charts. There is probably a better way, but I’d have to rebuild something so sorry!

Make the chart dual axis and synchronise the axis. Remove Measure Names from the All marks card.

Don’t show the Tooltip, remove all row/column dividers, hide the axis and the Attraction Name column. Hide all gridlines, axis lines, zero lines. Format the background of the workbook to be None (ie transparent).

Update the title of the sheet referencing the parameters as required, and name the sheet Tube Attraction Rank Bar or similar.

Adding the interactivity

Add the sheets onto the dashboard making use of layout containers to get the objects positioned where required. Format the dashboard to set the background to the light peach colour. How I’ve organised the content is show by the item hierarchy below

Create a parameter dashboard action

Select attraction

On select of the footfall bar chart, set the pSelectedAttraction parameter with the value from the Attraction Name field. Keep the value when the mark is deselected.

And at this point, you should hopefully now have a functioning dashboard. My published version is here.

Happy vizzin!

Donna

Can you rebuild this Tube Map?

Donna ColesLeave a comment

Lorna called on the help of a data schooler, Olivier Newman to set this week’s challenge, which will be part one of a 2-part challenge.

For those of you who are regular readers of my blog, you’ll know that working with maps and spatial data isn’t something I do often, so challenges like this always start with me feeling a little bit daunted by what’s required.

Side Note – I originally built this challenge using Tableau Desktop v2024.1, but encountered some issues with getting the data on the map updated as I made changes to the selections – the selection changes were visible on other tabular sheets, just not on the map, unless I forcibly refreshed the data source. Recreating in Tableau Desktop v2023.3 was fine. And the version published from v2024.1 to Tableau Public also worked fine on Tableau Public. I have raised this to Tableau via Slack channels I have access to, so if you experience similar issues, that may be why…

Understanding the data and the requirement

I initially spent some time trying to understand how the data matched up to the information I could see on the viz, specifically what was being listed in the Arrival Station selection box.

I found, every Station was associated with a Line, but the Station could be associated to more than one Line. Every Line was associated to a Branch, but again, the Line could be associated with more that one Branch. Picking some specific Stations as an example…

  • Amersham Station is associated to 1 Line (Metropolitan) which is associated to 1 Branch (Metropolitan Line Branch 0) – so Amersham is associated to 1 Branch
  • Bank Station is asscociated to 3 Lines (Central, Northern, Waterloo) which in turn are only associated to 1 Branch each – so Bank is associated to 3 Branches
  • Acton Town Station is associated to 2 Lines (District and Piccadilly); District is associated to 1 Branch which Piccadilly is associated to 2 Branches – so therefore Acton Town is associated to 3 Branches.

The list of possible Arrival Stations is based on the set of Stations associated to any of the Branches the Starting Station is associated to.

So for Amersham, we’re looking for all those Stations on the metropolitan branch 0 Branch

For Bank we’re looking at Stations on the central 0, northern 1 and waterloo 0 Branches

and for Acton Town, we’re looking at stations on the district 0, piccadilly 0 and piccadilly 1 Branches.

So first we need to find a way to

  1. Identify the Starting Station
  2. Identify the Branches the Starting Station is associated with
  3. Identify the Stations associated to these Branches.

Identifying the Arrival Stations

To start with, we need to capture the starting station, which we can do with a parameter

pStart

String parameter which is a List object that populates from the Station field when the work book is opened, and is defaulted to Bank.

For the rest, we’ll build up what we need step by step, so on a new sheet add Branch and Station to Rows and display the pStart parameter.

I’m first going to identify the possible Branches associated to the pStart station, and ‘spread’ this across all the stations in that Branch

Possible Branches

{FIXED [Branch] : MIN(IF [Station] = [pStart] THEN [Branch] END)}

If the Station in the row matches that in pStart, then get the Branch for that row, then ‘spread’ that across all the rows with the same Branch (via the {FIXED [Branch]: …. } statement.

Add this onto Rows and you’ll see the name of the Branch is listed against all the stations associated to the branch that the pStart station is related to

Now we can define a field to capture the stations that have a Possible Branch

Possible Destination Stations

IF NOT ISNULL([Possible Branches]) THEN [Station] END

Add this to Rows too, and stations should only be listed against those rows with a Possible Branch

We can use this field to then create a Set. Right click on Possible Destination Stations > Create > Set

Destination Stations Set

Select Epping from the list displayed

Add the field to the Colour shelf (the Epping row should be coloured IN the set). Then click on the pill on the Colour shelf and select Show Set

The list of possible options in the Destination Stations Set should be displayed. Change the control type to be single value dropdown

Now test the behaviour of the set by changing the value of the pStart parameter eg select Amersham. Epping remains selected but is now contained in ( ) as it’s not a valid value. The other options to select though should all now have changed.

This is the ‘relative values’ only type behaviour required.

Determining the number of stops

While we’re working with a ‘check sheet’, let’s finalise the other calculations we’re going to need to build the final viz; firstly the number of stops between the two selected stations. We’re going to use the Path Order field to help with this.

Firstly, if it’s appearing as a string in the data set, convert it to a numeric whole number field, then add it to Rows between Branch and Station It should be a discrete dimension (blue disaggregated field). A unique number should be listed against each record; this record is effectively an index defining the order of the Stations on the Branch.

Let’s reset the station parameters to start at Bank and end at Epping These stations are on the Central 0 Branch, and Bank is at Path Order 47 and Epping at 61

The number of stations is the absolute difference between these two numbers. To determine this, we need to capture the Path Order for the starting station against every row.

Now, it’s possible that the stations are on multiple branches, so we need to make sure we have a handle on the Branch we care about

Selected Branch

{FIXED: MIN(IF [Destination Stations Set] THEN [Branch] END)}

Get the Branch associated to the selected destination station, and then ‘spread this’ across all rows.

Add this to Rows.

Now we can get the number associated to the pStart station on the Selected Branch, and spread this across every row

Starting Station Path No

INT({FIXED: MIN(IF [pStart] = [Station] AND [Branch] = [Selected Branch] THEN [Path Order] END)})

as well as

Destination Station Path No

INT({FIXED: MIN(IF [Destination Stations Set] AND [Branch]=[Selected Branch] THEN [Path Order] END)})

Add both of these as discrete dimensions to Rows

Then we can create

No. of Stops

ABS([Starting Station Path No] – [Destination Station Path No])

which is just the absolute difference between the two

Identifying the stations between start & end

The final piece of the puzzle, that we’re going to need is just to isolate all the Stations on the Branch that lie between the pStart station and the station in the Destinations Station Set. As this is going to be used to highlight the section of line on the map, I called this

Highlight Line

[Path Order] >= MIN([Starting Station Path No],[Destination Station Path No]) AND [Path Order] <= MAX([Starting Station Path No], [Destination Station Path No])

Here I utilised the rarely used (at least in my case) feature of the MIN and MAX functions, that allows you to supply multiple values and return a single value – the MIN or the MAX of the options provided. So in this case, I want to flag all the rows as being true if the Path Order sits between the Starting Station Path No and the Destination Station Path No. Add this onto Colour instead of the In/Out set and we can see all the rows between the two endpoints are highlighted.

Test by trying different start and ends, so you’re happy how the behaviour is working.

Building the tube map

This did take a bit of time to get right, and I did end up referring to Tableau’s own KB article on creating paths between origin and destination to get some pointers (although I didn’t follow it to the letter…)

Create a new sheet, then create a spatial field

Station Location

MAKEPOINT([Right Latitude], [Right Longitude])

and double click to automatically add the field to the new sheet. Longitude and Latitude fields are automatically generated and a basic layout is immediately visible

Add Branch to Detail then change the mark type to Line.

Add Path Order to Path. The lines should all now join up as expected

Delete all the text from the Tooltip, but ensure Show Tooltip is still enabled.

Set the background of the map to dark (Map menu > Background Maps > Dark). Adjust the Colour of the line to whatever suits (I used #01e6ff)

Add a 2nd map layer – drag Station Location onto the canvas and drop when the Add a marks layer option appears

Change the Mark type of this 2nd marks card to circle, then add Station and Line to the Detail shelf. Change the colour to same as the line and adjust the Size if required. Update the Tooltip as required.

To highlight the stations between those selected, create a new spatial field, just for those stations

Selected Stations

IF [Highlight Line] THEN [Station Location] END

Drag this on to the canvas to make a 3rd marks layer.

Add Branch to Detail, change the Mark type to line and add Path Order to Path. Change the Colour to something contrasting (I chose #ff00ff). Adjust the Size so the line is a bit thicker than the other lines.

To label the start & end station, create

Label – Stations

IF [Station] = [pStart] OR [Destination Stations Set] THEN [Station] END

Add to the Label shelf, and change to be an attribute (rather than dimension) so it doesn’t break up the line. Adjust the font accordingly. I set it to Tableau Medium 8pt bold in white, aligned top centre. All the labels to overlap other marks.

Show the pStart parameter and the Destination Stations Set list (just right click on the field in the data pane on the left and select Show Set – this is now an option as there are fields already on the viz that reference that set). Test the display by changing the options.

Add No of Stops to the Detail shelf, then update the title to reference the field. Set the font to white and align right.

Format the background of the whole worksheet to black, remove row/column dividers. Hide the null indicator field, and remove all map options (Map menu > map options, uncheck all the fields).

The viz should now be ready.

Add it onto a dashboard, which is also formatted to have a black background. Display the pStart parameter and the Destination Stations Set as floating objects. Update the title of each and format the latter so it has a black shading to the body of the control. Remove the ‘all’ option from the arrival station control (customise > uncheck show ‘all’ value).

My published version is here. Hopefully I’ve built it in a way that supports the impending Part 2…

Happy vizzin’!

Donna

How far would total steps from TC23 respondents take you?

Donna ColesLeave a comment

As community month draws to a close, long term participant Deborah Simmonds set us a map based challenge based on TC23 data.

I chose to use the data that was associated to the solution workbook, rather than take the direct source, so bear that in mind if you’re following along.

Examining the data

As there were quite a few fields in the data set which were directly related to the solution, I just wanted to familiarise myself with what I was working with initially. Essentially we have a row per person (Names Full) with the hotel they stayed at (Label Hotels), and how many steps (Steps) they took each day (Date). The details of the convention centre (Label Convention Centre) exist against every row.

The LAT and LON fields contain the location details of the hotels, while Convention LAT and Convention LON contain the location details of the Mandalay Bay Convention Centre.

Names Full already had the logic applied to create names for users based on their User ID if the Name was NULL, so I didn’t need to do anything for that requirement.

We only want to consider records relating to those people who attended ‘In Person’ and who had provided a hotel. Consequently I added the following as data source filters (right click data source -> edit data source filters) to exclude unrequired records from the whole analysis.

  • Did you attend in person or virtual? : In person
  • Label Hotels : excludes NULL

Building the BANs

The BANs have 3 metrics – the number of attendees, the number of steps, and the distance in metres (based on the logic that 1 step = 0.75m).

Attendees

COUNTD([User ID])

Distance (m)

[Steps] * 0.75

On a new sheet add Date to Filter as a range of dates and show the filter control. Add Attendees, Steps and Distance (m) so the measures are displayed in a row.

Change the mark type to shape and add a transparent shape (see this blog for more details). Add Measure Names to Label too and then adjust label accordingly and align centrally.

Hide the header row (uncheck show header), remove row dividers and don’t show tooltips. Name the sheet BANs or similar. Adjust the date slider and the values should adjust.

Building the bar chart (viz in tooltip)

On a new sheet add Names Full to Rows and Steps to Columns. Apply the same Date filter (from the BANs worksheet, set the filter to apply to this new worksheet too).

The viz needs to display a reference line showing the overall average of the steps per person across the selected dates, regardless as to whether the records are filtered to a hotel or not.

What do I mean by this… well if I add a standard average reference line to the viz above, the average for the whole table is 78.2k steps.

If I now filter this by a Label Hotel, then the average changes, and I don’t want that – I still want to see 78.2k.

But the average does need to change if the date range changes

This took a bit of effort to get right, but I needed

Avg Steps

SUM({FIXED Date: SUM([Steps])})/SUM({FIXED:COUNTD([User ID])})

Format this as a number with 1dp set to the K (thousandths) level

and I also needed to add the Date field on the Filter shelf to context.

So reverting back to the initial view of the bar chart… right click on the Date filter and Add to Context. Add Avg Steps to the Detail shelf. Then add a reference line (right click the Steps axis > add reference line) that displays the Avg Steps with a dark dashed line with a custom label.

Format the reference line to position the label at the top and adjust the font style.

To colour the bars we need

Steps above average

SUM([Steps]) >=[Avg Steps]

Add this to the Colour shelf, change the colours and adjust the opacity to about 75%.

Hide the column heading, and adjust the font size of the names and the axis. Name the sheet Bars or similar.

Building the initial map

I decided to create 2 maps – one for the initial display of all the hotels and the convention centre, and then one for the selected location and buffer.

To plot the hotels on the map I created

Hotel Locations

MAKEPOINT([LAT],[LON])

On a new sheet, add this to the Detail shelf. A map will automatically generate with Latitude and Longitude fields. Change the Mark Type to Circle, then add Label Hotels to Label and align left middle. Edit the map Background Layers (via the map menu) to add Streets, Highways etc to the display

Add Steps, Attendees and Distance(m) to the Tooltip. Add Attendees to the Size shelf and adjust the size to vary by range

Apply the Date filter from the other worksheets to this sheet too. For the tooltip, We need to know about the min and max dates in the range selected. Create

Min Date

MIN([Date])

and custom format simply as dd (the day only)

Also create

Max Date

MAX([Date])

and custom form this as dd mmm yyyy

Add both of these fields to the Tooltip shelf. Adjust the text in the Tooltip and add a reference to the Bars sheet as a viz in tooltip (Insert > sheets > ). Adjust the height of the sheet to be 900.

The viz in tooltip should now display nicely on hover

To add the mark for the convention centre, we need

Conf Location

MAKEPOINT([Convention LAT], [Convention LON])

Drag this onto the map, and drop it when Add A Marks Layer displays

This will create a 2nd marks card. Change the mark type to shape and select the Tableau sparkle image if you have it stored. If not, just use another shape or circle (coloured differently).

Add Attendees to Size and add Label Convention Centre to Label and align left middle. Add Steps and Distance(m) to Tooltip and adjust to suit. Hide all the map options (map menu -> map options -> uncheck all the selections). Name the sheet Map – Initial or similar.

Building the ‘selected’ map

This will use parameters to identify what’s been selected – a hotel or the convention centre, so we need

pSelectedHotel

string parameter defaulted to empty string

and

pSelectedCentre

string parameter defaulted to empty string, just like above

The intention is that either both these parameters will be empty or only one will be populated.

To plot on a map we need

Selected Hotel Location

IF [pSelectedHotel] = [Label Hotels] AND [pSelectedCentre] =” THEN [Hotel Locations] END

and

Selected Centre Location

IF [pSelectedHotel] = ” AND [pSelectedCentre] =[Label Convention Centre] THEN [Conf Location] END

Duplicate the initial map sheet and name it Map – Selection. Show the two parameters and verify both are empty.

On the Hotel Locations marks card, drag the Selected Hotel Location field and drop it straight onto the Hotel Locations field. On the Conf Location marks card, drag Selected Centre Location and drop straight onto the Conf Locations field. Your map shouldn’t display anything…

Manually type ‘Luxor’ into the pSelectedHotel parameter. A mark should display. Adjust the Label of the Selected Hotel marks card so it is larger font, and aligned top middle. Set the colour to orange and remove the halo.

Remove the text from the pSelectedHotel parameter and manually type ‘Mandalay Bay Convention Centre’ into the pSelectedCentre parameter. A mark should display. Adjust the Label of the Selected Centre marks card so it is larger font, and aligned top middle. Remove the halo from the Colour shelf.

To create the buffer circle, we need to define the buffer radius, which is the attendee steps in metres.

Buffer Distance (m)

{FIXED : SUM(IF [pSelectedHotel] = [Label Hotels] OR [pSelectedCentre] = [Label Convention Centre] THEN [Steps] END)} * 0.75

and then we create

Buffer

IF [pSelectedHotel] <> ” THEN
BUFFER([Selected Hotel Location], [Buffer Distance (m)], ‘m’)
ELSEIF [pSelectedCentre] <> ” THEN
BUFFER([Selected Centre Location], [Buffer Distance (m)], ‘m’)
END

Add this as another marks layer.

Reduce the opacity on the colour shelf to 0% and set the border to be orange. We don’t want to allow any interactivity with the buffer, so disable selection of the layer, and also move down so it is listed at the bottom of the 3 map layers.

Show the Date filter control and adjust the dates to see the buffer adjusting. Test the behaviour with a hotel too (you may find you want to add some more detail to the background layers of the map).

We will use dynamic zone visibility on the dashboard to decide whether to display the initial or the selected map. To control this, we need

Show Initial Map

[pSelectedCentre]=” and [pSelectedHotel]=”

and

Show Selected Map

[pSelectedHotel]<>” OR [pSelectedCentre]<>”

Adding the interactivity

Create a dashboard, add the BANs and both the map sheets.

Create a dashboard parameter action

Set Hotel

On selection of the Initial Map set the pSelectedHotel parameter passing in the value from the Label Hotels field. When the selection is cleared, reset to ”.

and another parameter action

Set Conv Centre

On selection of the Initial Map set the pSelectedCentre parameter passing in the value from the Label Convention Centre field. When the selection is cleared, reset to ”.

Select the Initial Map object, and from the Layout tab, set the visibility to be controlled by the Show Initial Map field

Then select the Selected Map object, and set the visibility to be controlled by the Show Selected Map field. Only one of the maps should display based on the interactivity.

This is all the core functionality of the map, but Deborah threw in a couple of extra asks…

Building the Distance Legend

We’re using map layers again for this. Create a new field

Zero

MAKEPOINT(0,0)

Add it to the Detail shelf of a new worksheet to create the 1st map layer, then immediately add another map layer, by adding another instance of Zero to the sheet.

Switch the axis, and the map will disappear, and you’ll have axis displayed instead. Change the mark type of the first map layer to circle and colour orange.

Change the mark type of the 2nd map later to circle and colour pale grey with an orange border. Increase the Size of this circle so it appears as a ring around the filled orange circle. Move the 2nd marks layer down to the bottom and disable both marks from being selectable.

Hide the axis and gridlines/zero lines.

Right click on the central circle and annotate point. Don’t enter any text into the annotation box, just click OK. You should get the annotation box with a line.

Move the box so the connector line is horizontal, then format the annotation so the shading is set to none and the line is formatted to be a darker dashed line. Update the title of the sheet.

Building the Size Legend

Apply a similar process to that described above, but this time create 3 mark layers where the mark type is an open circle shape which is coloured blue, and for each layer, the size of the circle is slightly bigger. This time show the zero lines.

Set the background of both the legend sheets to be none (ie transparent), then add them as floating objects onto the dashboard. Use the control visibility feature to only display the Size legend when Show Initial Map is set, and only display the Distance legend when Show Selected Map is set. Set a background against each object of light grey, that is then set to 80% transparency.

With this you should have a completed challenge. My published version is here.

Happy vizzin’!

Donna

Can you build a trellis of Profit Ratio Gauges?

Donna Coles3 Comments

It’s Community Month at #WOW2024 HQ, and for the first challenge, Jack Hineman (a long time participant of WOW) asked us to create gauge charts using map layers. Not only that, he wanted them displayed in a trellis format, with a specific requirement to ensure the number of columns was always >= number of rows displayed. Errr…..

This was tough! I tried to start the challenge one evening and after pouring through Ken Flerlages’s blog post that was referenced, reading the hints, and looking at Jessica Moon’s Tableau Public page referenced, I was none the wiser. The blog post did not mention map layers at all in building a gauge, and was purely mentioned as inspiration for the design of the gauge.

I happen to have some time off work, so reattempted the challenge the next day. After several hours, I got there, somehow! I did another google : “Gauge charts in Tableau” and hit upon this blog, which gave me a few pointers, although most of the time it really was a lot of trial and error based on Jack’s hints, and to be honest I surprised myself that I actually hit all the requirements, except one, without the need to look at the solution.

The one thing I had to look at was the calculations required to get the trellis to always have more columns than rows. My ‘go to’ formula didn’t work. More on that later.

As for my solution… well it’s a solution…. how elegant/efficient it is – who knows. It was something built very much in stages as I tried to get my head around what was being asked. As I rebuild as part of the process I go through when writing this blog, I may find ways of improving what I did to start with. I will do my best to explain what I think is going on, what my thought process was, but apologise in advance if you get to the end of all this, and still don’t have a ‘scooby’ 😦

Strap yourself in! This is going to be a long one!!!!

Modelling the data

Connect to the provided data source and create relationship calculations to relate Manufacturers to Gauge_Definition with 1=1 and Gauge_Definition to Gauge_Points with 1=1 as well.

Understanding the data

Let’s start by looking at the data provided. Jack provided 3 data sets:

Manufacturers

A simplified instance of Superstore just listing Manufacturers with Sales & Profit data.

Gauge Definition

A data set of 1 row essentially containing some ‘constants’ to be referenced within the challenge

  • Gauge Success Amount = 0.15
    • Profit Ratios >= to 0.15 (15%) are deemed successful. This is essentially the Goal indicator value.
  • Gauge Concern Amount = 0
    • Profit Ratios >=0 (but < 0.15) are deemed a concern
  • Gauge Start Profit Ratio = -0.3
    • The left hand point on the semi-circular gauge should indicate a -30% profit ratio
  • Gauge End Profit Ration = 0.3
    • The right hand point on the semi-circular gauge should indicate a 30% profit ratio
  • Gauge Success Pct of Gauge = 0.75
    • 15% Profit Ratio represents 75% of the gauge displayed (ie 0% of gauge = -30% Profit Ratio and 100% of gauge = 30% profit ratio)
  • Gauge Concern Pct of Gauge = 0.5
    • 0% Profit Ratio represents 50% of the gauge displayed.

Gauge Points

This is essentially a template/scaffold to help build the gauge and the various features on the gauge. It defines all the points that need to be plotted and in most cases then connected to create the various ‘shapes’ displayed eg the gauge semi circle for the actual profit ratio and the legend indicator; the small angled rectangle that represents the goal ‘reference line’; the positions for the 3 labels.

To start getting an understanding, let’s just focus on Point Type = Actual and Point Segment ID = Background

This is the data to build the complete grey semi circle of the main gauge. 50 rows represent points on the inner arc of the semi circle (Point Arc = In). They all have a Point Radius = 0.43 (ie the distance from the 0,0 centre position of a circle to the bottom edge of the gauge is 0.43). The other 50 rows represent points on the outer arc of the semi circle (Point Arc = Out). They all have a Point Radius = 0.58 (ie the distance from the 0,0 centre position of a circle to the top edge of the gauge is 0.58). Point Angle Rads defines the angle in radians (rather than degrees) from the circle centre to edge of the circle. The Point ID defines the order to ‘join the dots’ when the points are made into a polygon.

Here’s a diagram to help try and explain the maths we’re going to need to use based on the data we have

For each point on the circle, we will need to identify the x & y position of where the radius intersects the edge of the circle. We know the angle, and we know the radius, so we can use trigonometry to work that out, and then use the MAKEPOINT() function in Tableau to covert that into a spatial/geometric field to use on a map.

Let’s do this in Tableau.

Create field

X

[Point Radius] *SIN([Point Angle Rads])

Y

[Point Radius] * COS([Point Angle Rads])

Note – based on my diagram above, X = a and would be derived from the Cosine of the angle, while Y = o and be based on the Sine of the angle. However, Jack gave hints based on the above calcs which hold true if you adjust the diagram and assume the angle is positioned between the y-axis and the radius, rather than the x-axis and the radius.

Now create the point

Geo

MAKEPOINT([X],[Y])

On a sheet, add Point Type to Filter and set to Actual, and add Point Segment ID to Filter and set to Background.

Double click on Geo to automatically add Longitude and Latitude fields to the sheet.

We have the basics of a semi-circle… not in the right direction, but it’s something… Add Point ID to Detail, then click the Swap Axis button and hey presto…

It appears a bit more ‘ovel’ than circular as the axis aren’t aligned, so don’t worry about this – set the display to Entire View will help. Then change the mark type to Line, move Point ID to Path and then change mark type to Polygon.

We now have a filled semi circle. We’re not going to use this sheet, but hopefully, this has helped a bit with some fundamental understanding.

When building we’re going to be using map layers (and at this point, we can’t add a layer to this sheet). We’ll also be defining calculations based on which feature of the viz we’re focussed on, as we can’t apply filters to the sheet (if you remove the ones applied, it will look a little crazy!). But if you change the Point Segment ID filter to Goal, you’ll get the shape of the goal indicator ‘reference line’.

You might want to play around with the filters to examine the behaviour.

Are you still with me…? Take a break, grab a cuppa, we haven’t even started building yet, but I’ll still be here when you get back 🙂

Setting up the map layers

Using Jack’s hints, create a field to help ‘initialise’ the map layers

Zero

MAKEPOINT(0,0)

Double click this to create a basic ‘map’ with a single point.

Then drag another instance of Zero onto the canvas and drop on the Add a Marks Layer section that appears

You’ll now have 2 marks layers, which means whatever we now do, we can always add more.

Building the Gauge Background & Legend layer

Note – in building I ended up with more mark layers than Jack suggested. I’ve subsequently seen other versions but am sticking to what I managed for now.

The first layer I’m going to build is the ‘grey’ semi circle of the main gauge and the coloured legend ‘inner’ semi circle.

I want to identify those points only.

Geo: BG-Legend Layer

IF [Point Type] <> ‘Label’ AND [Point Segment ID] IN (‘Background’, ‘Concern’, ‘Failure’, ‘Success’) THEN [Geo] END

On the Zero marks card, drop this field directly on top of the COLLECT(Zero) to replace it. Add Point ID to Detail, then flip the axis using the switch axis button. Add Point Segment ID to Colour and adjust the colours of the Background, Failure, Concern and Success values to suit.

Change the mark type to polygon, and move Point ID to Path. Name this layer BG & Legend

Building the Actual Layer

Create a new field

Profit Ratio

{FIXED [Manufacturer]: SUM([Profit])/SUM([Sales])}

and format to % with 1 dp.

We need to understand where on the gauge, the Profit Ratio for each Manufacturer falls. We know that the gauge starts at -30% Profit Ratio (ie 0% of the gauge is equivalent to -30% Profit Ratio) and the gauge ends at +30% Profit Ratio (ie 100% of the gauge is equivalent to +30% Profit Ratio). Therefore if the Manufacturer’s Profit Ratio >= 30% it fills 100% of the gauge, anything less needs to be partially through. We can calculate this (using one of Jack’s hints) with

PR % of Gauge

([Profit Ratio] + [Gauge End Profit Ratio]) / ([Gauge End Profit Ratio]- [Gauge Start Profit Ratio])

To then determine the angle in degrees (and again using Jack’s hints), we want to find the proportion of 180 degrees that the PR % of Gauge represents, and then take off 90 degrees based on the gauge rotation.

PR Angle (Degrees)

([PR % of Gauge] * 180)-90

We can then convert this to radians

PR Angle Rads

RADIANS([PR Angle (Degrees)])

This gives us information to help determine a singular point on the gauge we need to ‘draw’ up to. But I want to ‘draw’ a polygon that goes from the left end (-30% mark) to this point, and for this, I need to know all the other points up to that point.

The way I came up with isn’t what Jack did. My result means I don’t get an exactly accurate marker, but it is so close to it’s position, and is ‘good enough’ for the viz type and how it’s being displayed.

To understand what I did, build out a tabular sheet that is filtered to Manufacturer = Hon and Point Type = Actual, and shows Manufacturer, Point Segment ID and Point ID on Rows with Point Angle Rads, Profit Ratio and PR Angle Rads as measures.

The Profit Ratio for the Manufacturer =Hon is 6.4% which is at an angle of 0.34 radians around the semi circle.

You can also see that while we have values for the Point Angle Radians field associated to the Point Segment ID = Background, we don’t have any for the Point Segment ID = Actual, as this is what we’re trying to find out.

Given that I know that all the Point Angle Radians values associated to the Point Segment ID = Background build a complete semi circle, I figured, to display up to my ‘actual’ Profit Ratio, I just want to get all the points associated to background which are less than the PR Angle Rads value.

PR Point Angle Radians

IF [Point Angle Rads] <= [PR Angle Rads] THEN [Point Angle Rads] END

Pop this into the table, and when you scroll down, you’ll see I’ve only got values in my new field up to where the PR Angle Rads is less

Using this field, I’ll create some new X & Y fields which I can make make into a spatial field

X (actual)

[Point Radius] *SIN([PR Point Angle Radians])

Y (actual)

[Point Radius] * COS([PR Point Angle Radians])

Geo – Actual

IF [Point Type] = ‘Actual’ AND [Point Segment ID] = ‘Background’ THEN
MAKEPOINT([X (actual)], [Y (actual)])
END

On the Zero(2) marks card, Replace the COLLECT(Zero) pill with the Geo – Actual pill by dragging the latter and dropping it directly on the former. Add Point ID to Detail.

It’s drawing the points for a complete semi-circle, as every Manufacturer is being included. To help get the rest of the display right, for the various permutations, add Manufacturer to filter and filter to Hon, Bush, Logitech and Xerox. Add Manufacturer to Columns too. You should now see the marks stop at various positions around the arc. The filters will be adjusted later when we tackle the trellis.

Change the mark type to polygon and move Point ID to Path. Rename the layer to Actual.

For the colouring, we need to determine the RAG status of each Profit Ratio – where does the PR % of Gauge sit in comparison the constants we know

Actual RAG

IF [PR % of Gauge] <= [Gauge Concern Pct of Gauge] THEN ‘Failure’
ELSEIF [PR % of Gauge] <= [Gauge Success Pct of Gauge] THEN ‘Concern’
ELSE ‘Success’ END

Add this to the Colour shelf and adjust accordingly.

Building the Goal Indicator Layer

Create a new spatial field

Geo: Goal Layer

IF [Point Type] = ‘Actual’ AND [Point Segment ID] = ‘Goal’ THEN [Geo] END

and then drag this onto the canvas and drop on the Add A Marks Layer option.

Change the mark Type to Polygon and add Point ID to path. Add Point Segment ID to Colour and adjust the colour of the Goal value to suit. Rename the layer to Goal.

Building the Label layer

Create a new spatial field

Geo: Labels

IF [Point Type] = ‘Label’ THEN [Geo] END

and then drag this onto the canvas and drop on the Add A Marks Layer option. Add Point Segment ID to Detail. 3 marks should now displayed in the positions we need them

This bit took a bit of time to get right, as I had 3 requirements I wanted to satisfy: 1 – display a text or a numeric field as a label depending on what label I wanted to display (I attempted to have a single ‘label’ field converting numbers to strings with the relevant formatting, but the Profit Ratio % just wouldn’t show how I wanted when converted to string); 2 – adjust the colour of (some) of the labels depending on the RAG status of the profit ratio value; 3 – adjust the size of the Profit Ratio label based on how many gauges were displayed.

I needed several label fields

Label: Goal

IF [Point Segment ID] = ‘Goal’ THEN [Gauge Success Amt] END

formatted to % with 0 dp.

Label: Manufacturer-Fail

IF [Point Segment ID] = ‘Manufacturer’ AND [PR % of Gauge]<=[Gauge Concern Pct of Gauge] THEN [Manufacturer] END

Label: Manufacturer-Concern

IF [Point Segment ID] = ‘Manufacturer’ AND ([PR % of Gauge]<=[Gauge Success Pct of Gauge] AND [PR % of Gauge]>[Gauge Concern Pct of Gauge]) THEN [Manufacturer] END

Label: Manufacturer-Success

IF [Point Segment ID] = ‘Manufacturer’ AND [PR % of Gauge]>[Gauge Success Pct of Gauge] THEN [Manufacturer] END

Label: PR-Fail

IF [Point Segment ID] = ‘BAN’ AND [PR % of Gauge]<=[Gauge Concern Pct of Gauge] THEN [Profit Ratio] END

formatted to % with 1 dp

Label: PR-Concern

IF [Point Segment ID] = ‘BAN’ AND [PR % of Gauge]>[Gauge Concern Pct of Gauge] AND [PR % of Gauge]<= [Gauge Success Pct of Gauge] THEN [Profit Ratio] END

formatted to % with 1 dp

Label: PR-Success

IF [Point Segment ID] = ‘BAN’ AND [PR % of Gauge]>[Gauge Success Pct of Gauge] THEN [Profit Ratio] END

formatted to % with 1 dp

Add all these fields to the Label shelf, and adjust the label so that all are positioned on the same line, with no spaces, and add a carriage return beneath the text. Colour each field accordingly (DO NOT ADJUST THE FONT SIZE).

Change the mark type to text and align the label top centre. Rename the mark type to Labels and Disable Selection

To adjust the size of the labels, create a new parameter which we’ll need for the trellis.

pShowTop

integer parameter, defaulted to 7 which is a range from 5 to 81 with a step size of 1.

Show the parameter.

Create a new field

Label: Size

IF [Point Segment ID] = ‘BAN’ THEN [pShowTop]
ELSEIF [Point Segment ID] = ‘Manufacturer’ THEN 60
ELSE 80 END

We want the size of the BAN label to decrease as the number of manufacturers displayed increases.

Add this filed to the Size shelf as a continuous dimension (green pill, not aggregated).

Edit the Size legend so that sizes vary by range, the range is reversed, and the range starts from 1 to 81. Adjust the mark size range slider to a suitable start and spread.

As you change the value of the pShowTop parameter, the Profit Ratio BAN should adjust in size.

Format Sales and Profit to be $ with 0dp and to display as () when negative, then on all marks cards, add Manufacturer to Detail and Sales, Profit, Profit Ratio and Actual RAG to Tooltip, and adjust Tooltip on all the layers to suit.

Finally remove all gridlines/zero lines/axis ticks and hide the longitude & latitude axis. Hide the null indicator.

Building the Trellis

So now we’ve got the core viz nailed, we need to address the layout, which is to show a gauge for each of the top n manufacturers based on Sales. This means we need to have the gauges indexed/ranked from 1 to n based on total Sales, and then arrange in a grid so that top left is the manufacturer with the highest sales, and bottom right is the manufacturer with the lowest sales. For this we need to assign a row and column number against each manufacturer.

There are multiple blog posts about creating trellis charts. My go to post has always been this one by Chris Love, especially when the requirement is for the trellis to be dynamic (the number of rows/columns can vary) depending on the number of items to be displayed.

However in this instance, using the calculations referenced in the blog doesn’t meet the requirement of ensuring there are more columns than rows. This was an area that got me stumped. As a result, I finished the viz with a version that utilises my ‘go to’ calculations (published here), before then looking at Jack’s solution to get the calculations, which are

Cols Count

//If Rounded value = Value without Round then no remainder, use that number
if SIZE()/round(SQRT(SIZE()),0) = int(SIZE()/round(SQRT(SIZE()),0)) THEN SIZE()/round(SQRT(SIZE()),0)
//Otherwise add 1 to the number of columns
ELSE int(SIZE()/round(SQRT(SIZE()),0)) + 1
END

Size() is reflective of the number of items (in this case Manufacturers) to be displayed… as I write this down, for this specific instance, you could probably replace SIZE() with the parameter pShowTop.

Rowsv2

//For Each Manufacturer, what Row should it be in the Trellis?
//Rank the Manufacturer, Find the Integer portion when dividing by # of Columns
int((INDEX()-1)/ [Cols Count])

Colsv2

//For Each Manufacturer, what Column should it be in the Trellis?
//Rank the Manufacturer, Find the Remainder when dividing by # of Columns
int((INDEX()-1) % [Cols Count])

Make both Rowsv2 and Colsv2 discrete.

Add Rowsv2 to Rows and Colsv2 to Columns. Remove Manufacturer from Columns. It’ll look a bit odd, but be patient.

Edit the Manufacturer pill on the Filter shelf. On the General tab, select None, to remove everything from the filter, then on the Top tab adjust to be based on the top pShowTop by Sales

Now edit the table calculation associated to the Rowsv2 pill, so that it computes by specific dimensions and every field except Point ID is selected. Ensure Manufacturer and Point Segment ID are listed at the top in that order. Set the level to be Manufacturer and apply a custom sort based on Sum of Sales descending

As this is a nested table calculation, select the drop down arrow at the top and apply the same settings to the nested Cols Count field.

Then do exactly the same again for the Colsv2 table calculation settings. If all has been applied successfully, then you should get a grid

where you can then adjust the pShowTop parameter

Hide the Rowsv2 and ColsV2 fields from displaying (uncheck show header). Show the Longitude axis, and fix it to start at 0 but end ‘automatic’. Then hide the axis again (this ensures the arc lands on the row divider).

Then add the viz to a dashboard. My published version based on the trellis using Jack’s calculations is published here.

If you’ve made it to the end – well done! It was a bit of a marathon to do the challenge and another to write this blog. I’m sure it’s been quite an effort to read too, but hopefully you’ve learnt something, and I’ll certainly be referencing this again when a map layer and/or gauge based scenario occurs again.

Happy vizzin’!

Donna

Can you make dynamic indexed bars & measures?

Donna ColesLeave a comment

For this week’s #WOW2023 challenge, guest poster Ervin Vinzon asked us to rebuild this visualisation based on data from his home country, The Philippines.

I have to admit, I did find this a bit tough this week – there was a lot going on and maps don’t come naturally to me. I actually wasn’t sure initially whether both the files were needed, as the requirements were a little bit sparse, and I managed to build pretty much the whole solution not using the zip file. I just couldn’t get the map label annotation to work, so ended up having to had to revisit and start again.

Modelling the data

You will need to download both the excel file and the zip file from the Ervin’s shared area.

In the data pane, connect to the Ph Pop 2020 excel file and add the Philippine Population sheet to the canvas.

Then add a connection to a spatial file and point to the zip file. Tableau will automatically identify the file it can use. Add the Provinces file to the canvas.

Create a relation that uses relationship calculations that maps from the Philippine Population sheet :

IIF([Province] = “Maguindanao del Norte” OR [Province] = “Maguindanao del Sur”, “Maguindanao”, [Province])

to the the Provinces sheet

IIF([ADM1_EN] = “National Capital Region”, “Metro Manila”, [ADM2_EN])

Thanks to Rosario Gauna for helping me with this logic, as I couldn’t figure out how the data needed to be related. I think this really needed to be included in the requirements… (Note the logic has been adjusted since I took the image below)

Building the Measure Selector

We can’t use a parameter directly for this, as the design of the ‘radio button’ is more fancy than just what you get with the basic parameter selection functionality.

So we need to ‘fake’ the selection and can use existing fields in our data set to help with this. The Island Group field contains 3 values, so we’re going to draw on these and build

Measure Selector

CASE [Island group]
WHEN ‘Luzon’ THEN ‘By Population’
WHEN ‘Mindarao’ THEN ‘By Population Density’
ELSE ‘By Area’
END

Add to Columns and manually reorder. In the Rows shelf, double click and manually type MIN(0)Change the mark type to circle and add Measure Selector to the Label shelf. Resize the circles, and adjust the label to be aligned middle right. Change the view to Fit Width to see all the labels.

Create a parameter to capture the selected measure when this view is interacted with

pMeasureSelected

string parameter defaulted to By Population

Show the parameter on the sheet. Then create a calculated field

Is Selected Measure

[pMeasureSelected] = [Measure Selector]

and add to the Colour shelf. Adjust the colours to suit and add a grey border on the circles (via the colour shelf).

Stop the Tooltip from showing, hide the MIN(0) axis and the Measure Selector header and remove all gridlines/zero lines and any dividers. Name the sheet Measure Selection.

Building the bar chart

Firstly, we need to determine which measure we’re going to be displaying, so need

Measure to Display

CASE [pMeasureSelected]
WHEN ‘By Population’ THEN SUM([Population])
WHEN ‘By Population Density’ THEN SUM([Density])
ELSE SUM([Area (sq km)])
END

Show the pMeasureSelected parameter on a new sheet, then add Island Group and Province to Rows and Measure to Display to Text. Sort the data descending.

Create a new calculated field

Measure Rank

RANK_UNIQUE([Measure to Display])

Change the Measure Rank field in the left hand data pane to be discrete. Add to the Rows and adjust the table calculation so it is computing by Province only. The Measure Rank should show sequential numbers from 1 upwards, but restart at the next Island Group.

Add another instance of Measure Rank to the Filter shelf. Select All intially to select all the numbers. Then adjust the table calculation to compute by Province only as above. Then re-edit the filter and just select numbers 1-10.

The bar visual displays the actual value in a coloured bar, along with the maximum value for the measure in a grey bar. So we need

Max Value

WINDOW_MAX([Measure to Display])

Add this to the table and adjust the table calculation to compute by Province.

Finally, we need some information to help with the labels

Label Strapline

CASE [pMeasureSelected]
WHEN ‘By Population’ THEN ”
WHEN ‘By Population Density’ THEN ‘persons per sq km’
ELSE ‘sq km’
END

Add this to Rows and then test the behaviour by adjusting the value of the pMeasureSelected parameter.

We now have the data needed to build the bars.

Move Island Group to Columns and manually reorder to be Luzon, Visayas, Mindanao. Move Province and Label strapline to Text. Move Measure to Display and Max Value to Columns. Set sheet to fit Entire View. Reduce the size of the bar to be relatively thin.

On the Measure to Display marks card, add Island Group to Colour and adjust to suit.

Set the colour of the bar on the Max Value marks card to be pale grey and remove the bar border. Remove the Label Strapline field and move the Province from label to Detail.

Make the chart dual axis and synchronise the axis. Adjust the axis (right click > edit axis) to be independent axis ranges for each row or column.

On the Measure to Display marks card, add Measure Rank and Measure To Display to the Label shelf. adjust the table calculation settings of the Measure Rank field to compute by Province only.

Adjust the label to be aligned top left, and then format the label text box, so the label is laid out as required (I used bold 8pt font). To make the label sit ‘above’ the bar, add carriage returns after the text in the label edit box (thanks to Sam Parsons for spotting this sneaky method – my original build was using a much more complex method to get the text sitting on top of the bars!).

Finally hide the axis and the Measure Rank and Island Group fields. Remove all gridlines/zero lines/axis & row and column dividers. Stop the tooltips from showing. Name the sheet Bars.

Building the Bar Header

On a new sheet, add Island Group to Columns and manually re-order. Then double click in Columns and manually type MIN(0.1). Set the mark type to Bar and set the view to fit Entire View. Add Island Group to Colour. Reduce the Size of the bar. Edit the axis and fix to end at 0.7. Add Island Group to the Label shelf, and align bottom left. Adjust the size of the font to be larger and then add multiple carriage returns above the label text to shift the label to sit under the bar.

Remove all headers/axis and row/column dividers and gridlines. Stop the tooltip from showing.

Adjust the title of the sheet to reference the pMeasureSelected parameter.

Name the sheet Bar Header.

Building the map

We will need another parameter to store the selected Province value.

pSelectedProvince

string parameter defaulted to nothing

On. a new sheet, double click on the Geometry field. This will automatically display a map of the Philippines. Remove all the unnecessary detail via Map > Background Layers and unchecking all the options.

Add Province to the Detail shelf and Region and Island Group to the Tooltip. Adjust the Tooltip.

Show the pSelectedProvince parameter and manually enter the province Leyte.

Create a new field

Is Selected Province

[pSelectedProvince] = [Province]

and then add to the Colour shelf. Adjust the colours to suit (set the NULL field to the same as False).

We need to capture the ‘geometry’ of the selected Province

Selected Province Location

MAKEPOINT((IIF([Is Selected Province],[Latitude],NULL)),(IIF([Is Selected Province],[Longitude],NULL)))

Drag this field onto the canvas and drop it on the Add a marks layer section that displays. This will create a second marks card. Change the mark type to Circle and adjust the colour as required. Add pSelectedProvince to the Detail shelf.

Select the circle mark, and add an annotation against the mark (right click > Annotate > Mark). Reference the parameter pSelectedProvince in the dialog window.

Providing the pSelectedProvince is on the Detail shelf and is referenced in the Annotation, then changing the value of the pSelectedProvince parameter to Samar or any other province, should retain the annotation. Once again, thanks to Sam for figuring this out as I could just not see it, even when I looked at the solution.

Remove row & column dividers. Stop the map options from displaying (Map > Map Options and uncheck all selections). Update the title of the sheet, and then name the sheet Map.

Adding the interactivity

Add the sheets to a dashboard using horizontal and vertical layout containers to arrange the objects.

Update the title of the Measure Selection sheet and the Bar Header sheet to match the text being displayed.

Create a dashboard parameter action to define the measure selection on click

Set Measure

On selection of the Measure Selection sheet, set the pMeasureSelected parameter, passing through the value from the Measure Selector field.

Create another action for the Province

Select Province

On selection of the Bars sheet, set the pSelectedProvince parameter, passing through the value from the Province field. When the selection is cleared, reset to nothing.

To stop the Bar Heading sheet from being clicked on, just float a blank object over the top.

To prevent the other bars and the measure selections from all fading when clicked on, create a new field

HL

‘HL’

and add to the Detail shelf of the Bars sheet and the Measure Selection sheet.

Then back on the dashboard add a dashboard highlight action

Unhighlight

On selection of the Bars sheet and the Measure Selection sheet, target the Bars and the Measure Selection sheets using the HL selected field only.

Now when a bar is clicked, it will look ‘selected’ (has a black bar around it), but the other bars won’t become faded/greyed out. Similarly when a measure is selected, the other circles won’t fade.

Phew! That should be it. There’s a fair amount going on here and lots of tricky ‘gotchas’. My published viz is here .

Happy vizzin’!

Donna

Can you make a pie chart?

Donna ColesLeave a comment

In his final challenge for 2022, Luke set this challenge asking us to recreate this pie chart. Although not mentioned in the challenge text, there was a hint on the splash page that map layers would be required.

I’ve only really used map layers in other #WOW challenges, and they actually involve maps. This challenge was obviously a bit different – utilising a functionality built for one purpose in an entirely different way. I remembered when map layers were first released there was a big buzz about the potential possibilities, and had seen some examples, but I’d never gotten round to trying out for myself, so this was the perfect opportunity (and one of the many plus points as to why I love doing #WOW challenges).

So where to start… good question. If you read up on the official Tableau KLs relating to map layers, it’s all about geography, and while the data source does have geographic data (State, City etc), they aren’t relevant in this case. In my ‘googling’ I found the following resources of use

The first 2 blogs helped me understand the need for the use of the MAKEPOINT function, Sam Parson’s Pies & Doughnuts viz helped me understand the calculation I’d need for the MAKEPOINT function, and the final blog post really helped with putting in all together.

Feel free to ignore the rest of this blog and use the above to help you out 🙂

Building the first map layer

The first step is to create the geometry field we need to base this off of.

Zero

MAKEPOINT(0,0)

Double click this field, and it will automatically add the point centrally onto a map with Longitude and Latitude fields automatically generated too.

This is a key step in getting things started and enabling the use of map layers which we’re going to utilise.

Add Segment to Colour and adjust the colours. Change the mark type to pie chart and add Sales to angle. Increase the size to be as large as possible.

However the size isn’t as big as we need. To increase further use Ctrl-Shift-B (windows) or Cmd-Shift-B (mac) to increase the size further (Ctrl-B / Cmd-B) to reduce. This trick I found in the Interworks blog above. All Tableau key shortcuts are listed here.

Add Segment to the Label shelf. This completes our lowest map layer.

Building the second map layer

Drag Zero onto the map canvas, and drop it over the Add a Marks layer section that displays. This will add a second marks card called Zero(2).

On the marks card that is named Zero, rename it to Outer Pie.

On the marks card named Zero (2) rename to White Circle. Change the mark type to Circle, change the Colour to white and increase the size to leave a narrow border of the coloured pie underneath.

Building the third map layer

Drag another instance of Zero onto the canvas and add another marks layer. Rename Zero (3) to Inner Pie. Change the mark type to Pie chart and add Segment to Colour and Sales to angle. Increase the Size so it’s just smaller than the white circle. Change the opacity of the colour to 70% and add a white border (Colour shelf).

Adding the labels in the pie chart

The simplest way to do this is just to label the inner pie chart with the required fields and then manually move the labels from outside the pie to the desired location. However if your data changed in some way, eg the proportion of the slices changed, the labels may not be where you wanted without further tweaks.

So instead I’ve added a 4th map layer.

Add Zero once again to the sheet and add a marks layer. Rename this marks card to Labels -Inner Pie. Change mark type to Pie chart and add Segment to Detail, Sales to Angle and Sales to Label. Create a new calculated field

Pct

SUM([Sales]) / TOTAL(SUM([Sales]))

Format to % with 0 dp and and add to Label. Adjust the fonts of the labels so the Sales value is larger.

Increase the size of the pie chart so the labels are positioned ‘nicely’ within the segments of the Inner pie

Reduce the opacity of the ‘label’ pie chart to 0% and set the mark layer to be disabled

Finishing up

Adjust the tooltips to display as required (you’ll need to add Pct to the Tooltip shelf on both the Outer and Inner Pie mark cards).

Then remove the map background via the Map menu -> Background Maps -> None. Hide all axis and remove all gridlines/zero lines/row/columns dividers. You should now be left with a ‘clean’ pie chart which can be added to a dashboard.

My published viz is here.

Happy vizzin’!

Donna

Can you use multiple mark layers?

Donna ColesLeave a comment

Lorna Brown provided a refresher on map layers and spatial calculations for the #WOW2022 challenge this week. You’ll need Tableau Desktop v2020.4 or later to complete this due to the functionality incorporated.

The data set provided contains rows of origin & destination airports including the latitude and longitude values for each.

I found there were some fields in the provided data set which I don’t think should have been there. It meant when I came to naming some of my fields, I had to be more creative due to the existing ones.

We’ll start off by setting up the calculations required.

Firstly we need to create a spatial object out of our Origin and Destination airports.

Origin

MAKEPOINT([Origin Latitude],[Origin Longitude])

Destination

MAKEPOINT([Destination Latitude],[Destination Longitude])

Next we’re going to need to have a line to connect these

Origin-Dest Line

MAKELINE([Origin],[Destination])

We’re going to need ‘buffer’ to define the circle displayed. The size of this is to be defined by the user, so we’ll need a parameter

pBufferSize

integer parameter defaulted to 1000

and with this, we can then define the buffer

Buffer from Origin

BUFFER([Origin],[pBufferSize], ‘miles’)

Finally we need to determine whether the destination airport is within the buffer ‘zone’.

Within Buffer

[Distance (Miles)]<=[pBufferSize]

Note: Distance (Miles) already existed within the downloaded data set. I was expecting to have to calculate the distance myself, given the nature of the challenge. If I had had to create it, I would have used the calculation DISTANCE([Origin], [Destination], ‘miles’)

This is all we need to build the viz. I’m going to start from the top – down ie Origin airport -> Destination airport -> Lines – >Buffer.

On a new sheet, add Origin Airport to Filter and set to LAS. Also add Within Buffer to the Filter shelf and set to True.

Then drag Origin onto the main canvas area and drop it when you see ‘Show Me’ displayed on the cursor. This will automatically add all the required fields into the relevant locations

Change the mark to a circle, increase the size and set the colour to black. Add Origin Airport to Label and Origin Name to Tooltip, and adjust the tooltip accordingly.

This is the first map layer.

Now drag Destination onto the canvas and drop it on the ‘stacked layer’ icon when you get the Add a Marks Layer option appear

This will create a new marks card on the left, and is the 2nd marks layer.

Add Destination Name to the Detail shelf, then change the mark type to square. Add Destination Airport, Origin Airport and Distance (Miles) to Tooltip and adjust tooltip to match.

Finally move the Destination marks card so it is below the Origin marks card. Click on the Destination card and drag to below the Origin card and drop when you see the orange line appear

Now drag Origin-Dest Line onto the canvas and drop it on the ‘stacked layer’ icon when you get the Add a Marks Layer option appear to create the 3rd marks layer. This will add all the ‘spokes’.

Change the colour to grey. Add Destination City to the Detail shelf. Add Origin Name, Origin Airport, Distance (Miles) and Destination Airport to the Tooltip and adjust accordingly. Finally, drag this marks card so that it is now below the Destination marks card.

Final layer now – the buffer zone.

Drag Buffer from Origin onto the canvas and drop it on the ‘stacked layer’ icon when you get the Add a Marks Layer option appear to create the 4th marks layer. Adjust the colour to light grey, and reduce the opacity to suit. Then move this marks card to the bottom, so its beneath the Origin-Dest Line marks card.

And that’s it. Add the sheet onto a dashboard, and show the Origin Airport filter as a Single Value dropdown so only 1 origin airport can be selected at a time. I also customised the control so the All option did not display either. Add the pBufferSize parameter to the display too, and test the viz by changing the size and the airport.

My published version of the viz is here.

Happy vizzin’!

Donna

Can you build an app to visualise wildfires?

Donna ColesLeave a comment

Ann Jackson’s husband Josh (@VizJosh) set the challenge this week, to build an ‘application’ to help visualise the scale of wildfires; that is when a fire is said to be 5000 acres, you can use the app to view how that compares to an area of the world you may know, so you can really appreciate just how large (or small) the fire is.

I have to hold my hand up here, and say that after reading the requirements several times, I was absolutely stumped as to where to start. We were provided with some ‘data’ to copy which consisted of 5 rows, which I duly copied and pasted into Desktop, but I then like ‘what now….?’ I knew I needed something geographic to build a map, but couldn’t understand the relevance of the 5 rows… I’ve said before I don’t use maps that often, so was unsure whether there was something I needed to do with this data. After staring at the screen for what seemed like an age, I ended up looking at the solution.

The data is just ‘dummy’ data and is just something to allow you to ‘connect’ Tableau to. You can’t build anything in Tableau without a data source. It could just have been 1 row with a column headed ‘Dummy’ and a value of 0. If it had been that, it might have been more obvious to me 🙂

  • Defining the parameters
  • Building the map
  • Apply button
  • Dashboard Actions

Defining the parameters

Ultimately the ‘data’ being used to build the viz is driven by parameters – the Location selector and the Latitude & Longitude inputs.

pLocation

An integer list parameter that stores values, but displays worded locations – wherever you choose. I opted for my hometown of Didcot in the UK alongside locations Josh had used, mainly so I could validate how the rest of the ‘app’ would work when I came to build it.

pLongitude

Float input, defaulted to the longitude of location 1 (ie Didcot) above.

I just googled Didcot Latitude and Longitude to find the relevant values

Note – Longitude W means an input of -1 * value. Similarly for Latitude S needs to be a negative input.

Then I created

pLatitude

Since we’re talking about parameters, there’s a couple more required, so lets create them now

Acres

Integer parameter defaulted to 5000

pZoom

Integer, list parameter with the values below, defaulted to 2.

Building the map

Now we have some lat & long values (in the pLatitude and pLongitude parameters), we can create some geographic data needed to build a map.

Location

MAKEPOINT([pLatitude], [pLongtitude])

This gives us the centre point which we want to build the ‘fire size’ buffer around. For this we need the calculation JOsh kindly provided :

Acres to Feet

SQRT(([Acres]*43560)/PI())

and then we can create the buffer

Fire Size

BUFFER([Location],[Acres to Feet],’ft’)

Double click on this field and it should automatically create you a ‘map’

Adjust the map ‘format’ via the Map > Map Layers menu option. I chose to set it to the dark style at 20% washout, then ticked various selections to give the details I needed (I added and removed options as I was testing against Josh’s version). I also set the colour of the mark via the Colour shelf to be pale red.

Also, as per the requirement, turn off the map options via Map > Map Options menu, and unchecking all the selections.

So this is the basic map, and you can input different lats & longs into the parameters to test things out.

Now we need to deal with the zoom requirement.

I wasn’t entirely sure about this, so had a bit of a search and found Jeffrey Shaffer’s blog post How to create a map zoom with buffer calculation in Tableau – bingo!

The zoom had to be x times the size of the circle on the map, so achieved by

Zoom

BUFFER([Location],[pZoom] * [Acres to Feet],’ft’)

Add this a map layer (drag field onto the map and drop onto the Add a Marks Layer section that displays)

This has generated a 2nd circle and consequently caused the background map to zoom out. We don’t want this circle to show, nor to be selected, so on the Colour shelf, set the Opacity to 0%, and the Border and Halo to None. To prevent the circle from showing when you hover your mouse on the map, you need to Disable Selection of the Zoom marks card

Apply Button

On a separate sheet, double click into the space below the Marks card, and type ‘Apply’ into the resulting ‘text pill’ that displays, and then press return.

This will create a blue pill, which you can then add to the Label/Text shelf. Align the text to be middle centre

This view is essentially going to act as your ‘Apply’ button on the dashboard. When it is clicked on, we want it to take the Lat & Long values associated to the place listed in the pLocation parameter, and update the pLatitude & pLongitude parameter values.

For this, we need a couple of extra calculated fields

Location Lat

CASE [pLocation]
WHEN 1 THEN 51.6080
WHEN 2 THEN 40.7812
WHEN 3 THEN 51.5007
WHEN 4 THEN 48.8584
END

Note – as before, all these values were worked out via Google as shown above.

Location Long

CASE [pLocation]
WHEN 1 THEN -1.2448
WHEN 2 THEN -73.9665
WHEN 3 THEN 0.1246
WHEN 4 THEN 2.2945
END

Add both these fields to the Detail shelf of the Apply sheet.

Dashboard Actions

When you add the 2 sheets to the dashboard, you then need to add parameter actions to set the values of the pLongitude & pLatitude parameters on click of the Apply button

Set Lat

A parameter action that runs on Select of the Apply sheet, setting the pLatitude parameter with the value from the Location Lat field.

You need another action Set Long which does a similar thing by passing the Location Long field into the pLongitude variable.

Finally, you don’t want the ‘Apply’ button to look ‘selected’ (ie highlighted pale blue) once clicked. Create calculated fields True = True and False = False and add both of these to the Detail shelf on your Apply button sheet.

Then add a dashboard filter action that uses Selected Fields and maps True to False

Hopefully, this should provide you with all the core features to get the functionality working as required. Ultimately once I got out of the starting blocks, it wasn’t too bad…

My published viz is here.

Happy vizzin’! Stay Safe!

Donna

Can you visualise the Cholera Outbreak?

Donna ColesLeave a comment

Lorna delivered an exciting map based challenge this week, to recreate one of the most famous visualisations ever created. If you’re part of the data viz community and never heard of John Snow and his cholera map, then I suggest you go and google now 🙂

While I love map based challenges, as its an area I don’t get to use regularly, they’re also the ones that can give me the most frustrations/take the longest to complete, as the functions and concepts I need to use don’t come as readily as with other challenges. I had to refer back to my own blogs on previous map based challenges (specifically this one and this one), to help me out. However these were written before map layers were introduced, so not everything was applicable.

  • Modelling the data
  • Building the Avg Distance to Pump bar chart
  • Building the Total Deaths within Avg Distance bar chart
  • Building Map
  • Adding the dashboard interactivity

Modelling the data

3 sets of data was provided

  • Pumps – 1 row per pump with its location
  • Deaths – 1 row per death and its location (can be multiple rows for the same location)
  • Deaths aggregated – 1 row per location where at least 1 death was recorded, including the count of deaths at that location

This all needed to be ‘combined’ so we can work across all 3 sets of data and compare the locations. I used relationship calculations to create a relationship of 1=1 between the related data sets, which means all the aggregated deaths are mapped to each pump, and all the individual deaths are mapped to each pump too.

Building the Avg Distance to Pump bar chart

I chose to start building the bar charts first so I could get better acquainted with how the data was working together, and I knew the maps would take more effort.

To start we need to figure out the distance from each pump to each death, so we need to get the location of each pump, and the location of each death

Pump Location

MAKEPOINT([Pump Lat],[Pump Lon])

Individual Death Location

MAKEPOINT([Death Lat],[Death Lon])

These will both create calculated fields of a geographic data type as indicated by the globe icon to the left of the field.

And with these fields, we can then work out the distance between them in metres

Distance Pump to Death

DISTANCE([Pump Location], [Individual Death Location],’m’)

Now we want the average distance per pump

Avg Distance

{FIXED [Pump ID]: AVG([Distance Pump to Death])}

I formatted this to 0 dp and added a suffix of ‘m’

And with this, we can build the first bar chart – Pump ID on Rows and Avg Distance on Columns. You need to apply formatting

  • Change the font – I set the font to Times New Roman at the Workbook level, to make life easier (Format menu > Workbook).
  • Set the worksheet background colour. I used #f5f1f0
  • Add a black border to each bar (via the Colour shelf)
  • Show labels on bars (via Label shelf)
  • Hide Avg Distance axis (uncheck show header on the Avg Distance pill)
  • Remove all row & column borders
  • Set the Axes Ruler on Rows to black
  • Set the Tooltips

A parameter is needed to store the selected pump

pSelectedPump – an integer defaulted to 1

With this, we can then create a field to indicate which pump is selected

Is Selected Pump?

[Pump ID]=[pSelectedPump]

Add this field to the Colour shelf and set the True option to black and the false option to match the background colour you used.

Building the Total Deaths within Avg Distance bar chart

We now need to identify if the death occurred within the average distance that has been calculated.

Number Deaths within Avg Distance

SUM(INT([Distance Pump to Death] <= [Avg Distance]))

This is a bit of short hand instead of writing IF [Distance Pump to Death] <= [Avg Distance] THEN 1 ELSE 0, and summing up the result. It relies on the the fact that the equation [Distance Pump to Death] <= [Avg Distance] returns a boolean of true or false, which can be converted to an integer as true =1 and 0 = false.

At a row level, the field just returns 1 or 0, but just plot this field against Pump ID, you get the desired count

And the easiest way to build this bar chart, is to duplicate the one created above (on the worksheet tab, right click & duplicate sheet), then replace the Avg Distance pill with the Number Deaths within Avg Distance pill (simply drag the latter from the data pane and drop directly onto the former in the columns shelf). Then adjust tooltips etc to suit. Doing it this way preserves (most of) the formatting.

Building the Map

We’re going to use 4 layers in creating the map, and I’m documenting from the bottom upwards (although this isn’t the order in which I actually built the viz in practice – I shuffled things round afterwards).

We’ll start with the density layer – the blue coloured area on the map.

On a new sheet, add Individual Death Location and Death ID to the Detail shelf. This should automatically create a map view with the auto generated lat & long fields. Then

  • Change the mark type to Density
  • Change the colour to Density Blue-Teal Light
  • Alter the Intensity to 75%, the Opacity to 60%
  • Increase the Size to maximum
  • Delete the info in the tooltip

We need to set the background map

Via the Map > Map Layers menu option, set the Style to Normal and uncheck all options and set Streets, Highways, Routes

Then set the worksheet background to the colour we’ve used before

Onto Layer 2 – the pump buffer circle.

We’ve already identified the selected pump, but now we need to get it’s location, and for that we need the lat and long of the selected pump.

Selected Pump Lat

{FIXED: MIN(IIF([Is Selected Pump?],[Pump Lat],NULL))}

This essentially gets the latitude of the selected pump and sets that value across all the rows in the data.

Selected Pump Long

{FIXED: MIN(IIF([Is Selected Pump?],[Pump Lon],NULL))}

And with these we can get

Selected Pump Location

MAKEPOINT([Selected Pump Lat],[Selected Pump Long])

We also need to get the average distance of the selected pump spread across every row

Selected Pump Avg Distance

{FIXED :SUM( IF [Is Selected Pump?] THEN [Avg Distance] END)}

Now we have this, we can build the buffer field

Pump Buffer

BUFFER([Selected Pump Location],[Selected Pump Avg Distance],’m’)

Drag this Pump Buffer field onto the map and drop it onto the ‘Add a Marks Layer’ section that should appear. This will create an additional marks card.

Set the colour to the same background colour previously used, and drop the opacity to around 5%. Add Pump ID to Detail and Selected Pump Avg Distance to the Tooltip shelf. Adjust tooltip to match.

Onto Layer 3 – the pumps

Drag Pump Location onto the map and Add a Marks Layer.

Add Pump ID to Text and Location to Tooltip to the relevant marks card. Change mark type to circle, increase the size and change colour to red and add a dark grey border. Adjust text to be centred, and set the tooltips accordingly.

Onto the final layer now, the aggregated death locations. We need a further location field

Death Location

MAKEPOINT([DeathLat (deaths aggregate.csv)], [DeathLon (deaths aggregate.csv)])

Drag this onto the map to Add a Marks Layer then on the subsequent marks card add Loc ID to the Detail shelf. Change the mark type to circle, and add Deaths to the Size shelf – adjust accordingly. Change the colour to black with a white border. Adjust tooltip.

Adding the dashboard interactivity

Add the 3 sheets onto a new dashboard sheet. Create a new dashboard action to Change Parameter, that runs on select of any of the 3 charts, and targets the pSelectedPump parameter by setting it with the value from the Pump ID field.

Now if you select a pump on the map, or a bar on either of the bar charts, all the charts will reflect the selection made.

The other interactvity you may notice, is that on click, of the bars, or the pumps, the other data ‘fades’ (or the selected data is highlighted). We don’t want this.

To resolve, create a calculated field

True

True

and another

False

False

Add both these fields to the Detail shelf on both bar chart sheets and to the Detail shelf on the Pumps marks card.

Then on the dashboard, create a dashboard filter action which filters on selected fields setting True = False (see below). You’ll need to create one of these actions for each of the 3 sheets.

And hopefully, you now have a working viz. My published version is here.

Happy vizzin’! Stay Safe!

Donna

Can you use spatial BUFFER() functions in two ways?

Donna Coles1 Comment

Week 10 of #WOW2020 was set by guest challenger Sean Miller, who chose to demonstrate a ‘hot off the press’ feature released in v2020.1 (so having this version is a prerequisite to completing this challenge).

I was excited to see this as I don’t use maps often in my day job, and I love being able to have the opportunity to try the new stuff.

Sean provided references to two blog posts, which are a must read as they will definitely help guide you through the challenge, and explain in more detail what’s going on ‘under the bonnet’. I’m not therefore going to repeat any of this.

Sean provided 2 versions for the challenge with supporting datasets.

Intermediate challenge – Can you isolate pubs within 500m of a hotel?

For this we are provided with a set of hotels in London and a set of pubs. The requirement is to only include on the display the pubs which are within a 500m radius (ie buffer) of each hotel.

Join the data

The provided data consisted of a sheet of Pubs with a Lat & Lon field, and a sheet of Hotels with a LAT & LON field

These 2 data sets need to be Inner Joined together as

(Pubs data) MAKEPOINT([Lat],[Lon])

INTERSECTS

(Hotels data) BUFFER(MAKEPOINT([LAT],[LON]),500,’m’)

In the join clause window, you have the option to Edit Join Calculation which lets you type the calculation you need

Mapping the Hotels

Whilst the join has been made, we will need the ‘buffer’ calculation to display on the viz, so create

Buffer Hotel

BUFFER(MAKEPOINT([LAT],[LON]),500,”m”)

Then double click the Latitude (generated) and Longitude (generated) fields which will automatically display a map on screen.

Add Buffer Hotel to the Detail shelf and you’ll get the following (and the mark type will change to Map)

The circles look to be representing each hotel, but if you hover over one circle, all get selected. Add Hotel Name to Detail to allow individual selection.

Add Number of Records to the Label shelf, and format to suit.

Change the Colour of the mark to be pale orange and adjust the Opacity to suit.

Set the map background by choosing Map -> Map Layers from the menu and selecting Streets from the background style section

Mapping the Pubs

As with the hotel, we’re going to need the Pub Location spatial point to display on the viz, so create

Pub Location

MAKEPOINT([Lat],[Lon])

Duplicate/drag another instance of Latitude (generated) onto the Rows shelf.

On the second marks card, remove all the fields, and change the mark type to circle, then add Pub Location onto the Detail shelf, along with Pub Name.

You might be struggling to see the marks, but they are there – change the colour to grey, add a white border and adjust the size… found them?

The Tooltip on the pub marks, displays the distance from the hotel to the pub, so create

Distance

DISTANCE(MAKEPOINT([Lat],[Lon]), MAKEPOINT([LAT],[LON]), ‘m’)

which is the distance in metres from the Pub Location to the Hotel Location (I could have used my Pub Location field and created a Hotel Location field to put into this calculated field.

Add Distance to the Tooltip field for the pub marks, and adjust to match.

Now make dual axis

Hotel List – Viz in Tooltip

On hover over the hotel buffer circle, a full list of the pubs in range is displayed. This a managed using another sheet and the Viz in Tooltip functionality.

Create a basic table with Hotel Name, Pub Name on Rows and Distance on Text. Type in the word ‘Distance’ into the Columns to make a ‘fake’ column label.

Hide Hotel Name from displaying by unchecking Show Header on the field, then Hide Field Labels for Rows and Hide Field Labels for Columns. Format to remove the column divider

Name the sheet Pubs or similar

On the Tooltip of the hotels buffer marks, adjust the initial text required, then insert the sheet by Insert -> Sheets -> <select sheet>

This will insert text as below

At the point it says ‘<All Fields>’, delete the text, then Insert -> Hotel Name

Now, if you hover over the buffer circle on the map, the list of pubs associated to just that hotel should display.

Note – when adding the sheets into the viz in tooltip, or changing the fields to filter by, always use the insert & select options rather than just typing in, as I find it doesn’t always work otherwise….may be just me though….

Phew! That’s the intermediate challenge completed (well once you’ve tidied and added to a dashboard of course.

onto the next….

Jedi Challenge – Can you find the pubs closest to a chosen hotel?

Sean provided a separate pre-combined dataset for this, as the display needs to show all the pubs, regardless of which hotel is selected, whereas in the intermediate challenge, the spatial join meant all the pubs outside of the buffer zones were excluded.

The map itself follows very similar principles. We need a dual axis, where one axis is plotting a selected hotel with it’s buffer, and the other axis, the pub locations.

The selected hotel is ultimately going to be derived from a parameter action, but we’ll set that later. For now, let’s just create the string parameter, Selected Hotel, to store the name of the hotel, which is just set to a ‘default’ value of “The Hoxton – Shoreditch”

Additionally, the buffer radius can be changed in this challenge, so we have another parameter, Buffer Radius, this time an integer with a max value of 500, and defaulted to 500 as well.

To draw the selected hotel with buffer on the map, we first need to isolate the selected hotel’s latitude & longitude, to determine the location, and store it against every row in the dataset via a LoD calculation

Is Selected Hotel?

[Name]=[Selected Hotel]

Selected Hotel Lat

{FIXED : MIN(IIF([Is Selected Hotel?], [LAT],NULL))}

Selected Hotel Long

{FIXED : MIN(IIF([Is Selected Hotel?], [LON],NULL))}

Selected Hotel Location

MAKEPOINT([Selected Hotel Lat],[Selected Hotel Long])

Now we know the location, we can create the buffer around it

Hotel Buffer

BUFFER([Selected Hotel Location],[Buffer Radius],’m’)

The Hotel Buffer and the Selected Hotel parameter are needed to display the hotel on the map.

We then need to create the fields used to display the pubs.

Pub Name

IF [Location Type]=’Pub’ THEN [Name] END

Pub Location

IF [Location Type]=’Pub’ THEN MAKEPOINT([LAT],[LON]) END

You should now be able to create the map following the steps outlined above in the intermediate challenge. One axis will show the buffer around the selected hotel, the other will show all the pubs.

The pubs need to be sized & coloured based on the distance from the selected hotel, so we need

Distance Selected Hotel-Pub

DISTANCE([Selected Hotel Location],[Pub Location],’m’)

Add this to the Size & Colour shelf of the pubs marks card, and adjust to suit (you’ll need to reverse the colour range). Also note, there are 2 pubs named Alchemist, so add Neighbourhood to the Detail shelf too to make sure the distance calcs returns the correct values. Update the tooltip on the pubs mark too.

Finally

  • update the tooltip on the pubs mark
  • add the Selected Hotel parameter to the Label of the hotel mark and adjust font to suit
  • remove the tooltip from the hotel mark

At this point the main map is built, but Sean has added a bit extra to this challenge, a bar chart to drive the hotel selection with a sort selector to drive the ranking of the hotels; all of this is wrapped up in a collapsible container – phew!

Let’s break this down and start with the bar chart.

Hotel Selector Bar Chart

Build a bar chart as follows :

  • Name, Yelp Rating (as discrete field), Price Rating on Rows
  • Yelp # of Ratings on Columns
  • Location Type = Hotel on Filter
  • Is Selected Hotel on Colour
  • Show mark labels so Yelp # of Ratings is displayed at the end of the bars

Adjust formatting to match (remove column/row lines, set the row banding, hide headers etc)

Set the Alias of the Price Rating field, so Null displays as <blank>

Name the sheet Hotel List or similar.

On a dashboard, add the Hotel List and the Map, so we can create the parameter action (Dashboard -> Actions -> Add Action -> Set Parameter) to interact between the list and map.

Clicking a hotel in the bar chart should now change which hotel is selected in the map.

Bar Chart Sort Selector

The bar chart can be sorted based on the 3 measures displayed; Price Rating, Number of Ratings, YELP Rating. We need to build the selector to allow a choice, and then change the bar chart based on the selection. This again is parameter actions, and builds on techniques used in previous WoW challenges blogged about here and here and here.

As a result, I’ll be relatively brief about how the selector is built, as the blogs should help with this.

I used 3 instances of MIN(0.0) on the Columns, and aliased the Measure Name of these to ‘ Yelp Rating ‘, ‘ Price Rating ‘, ‘ Number of Ratings ‘ (Note the spaces either side). I also adjusted the axis of each measure to make them all appear left aligned,(this was a bit trial & error).

I also needed a parameter Selected Sort Measure defaulted to ‘ Price Rating ‘

Three calculated fields are used to set the Shape of the displayed mark for each measure

Sort – Price Rating

[Selected Sort Measure] = ‘ Price Rating ‘

Sort – Number of Ratings

[Selected Sort Measure] = ‘ Number of Ratings ‘

Sort – Yelp Rating

[Selected Sort Measure] = ‘ Yelp Rating ‘

I also added the True = False url action trick to ensure the marks all appeared ‘selected’ when only one was selected.

To invoke the sort on the bar chart itself, create a calculated field

Chart Sort

CASE [Selected Sort Measure]
WHEN ‘ Yelp Rating ‘ THEN SUM([Yelp Rating])
WHEN ‘ Price Rating ‘ THEN SUM([Price Rating Sort]) * -1
WHEN ‘ Number of Ratings ‘ THEN SUM([Yelp # of Ratings])
END

Note the Price Rating Sort field is multiple by -1 to ensure it displays from lowest to highest on the sort, whilst the other fields will display highest to lowest.

Alter the Hotel Name field on the Hotel list bar chart to sort descending by Chart Sort

Add the Sort Selector sheet to the dashboard, and add a parameter action

You should now be able to play around, selecting a sort option to change the order of the hotel list, then selecting a hotel to change the map.

Hiding the hotel list / sort selector

On the dashboard add a vertical container, then place the Sort Selector sheet and the Hotel List bar chart inside.

Remove the chart titles, set the background of the container to white, then set the container to be floating and select the container option to Add Show/Hide Button.

A Cross image will appear, select to Edit Button and change the button style to Text Button

In the Title section enter the required text for when the section is displayed (Item Shown) and then for when the section is collapsed (Item Hidden). Adjust the font too.

After hitting apply, the button section, will need resizing to get the text to display

The show/hide functionality needs to be manually selected on Desktop. When on server the interactivity will work. So to close the container, on the button menu, select Hide

and the container with the selector and the bar chart will disappear

Now it’s all just about finalising the dashboard to display all the objects in the appropriate locations. The colour/size legend and Buffer parameter are also within a container, which is floated and positioned bottom left.

Hopefully I’ve covered everything. There’s a fair bit going on in this Jedi version!

My published versions are here.

Happy vizzin’!

Donna