For the bikes, we need to know how much charge it has left
Charge %
SUM([Current Range Meters]) / SUM([Max Range Meters])
format this to % with 0 dp
Add Bike Location to a new sheet. Add Bike Id to Detail and change the mark type to circle. Add Charge % to Colour, and adjust the colour palette as required, and also edit so it is fixed to range from 0 to 1 (ie 0-100%).
Adjust the opacity of the colour to around 70% and add a pale grey border around the circles. Click on the 1 null indicator to the bottom left and select filter data to exclude that record from the display.
Select Map > Map Options from the menu and uncheck all the values to prevent the map from bing manually zoomed in/ changed. Then select Map >Background Layers from the menu, and set the Style to dark and click the Streets,Highways etc map option.
Drag Station Location onto the canvas and drop when the Add a Marks Layer option appears. Add Name the Detail shelf and Num Bikes Available to Colour. Change the mark type to square and adjust the colour palette as required and fix to range from 0 to 50.
Adjust the opacity of the colour to around 70% and add a pale grey border around the circles. Then move the stations marks card so it is listed below the bikes marks card. This means the bikes are displayed ‘on top’
Identifying the selected bike
Create 3 parameters
pSelectedBike
string parameter defaulted to <empty string>
pLat
float parameter, defaulted to 38.9358 (this is the central point mentioned in the requirements)
pLon
float parameter defaulted to -77.1069 (this is the central point mentioned in the requirements)
Note – originally I planned to just capture the ID of the selected bike then determine the lat & lon of that bike using a FIXED LOD to in turn determine the selected bike’s location, but that really hampered the performance, so I just used the parameter action to capture the required Lat & Lon directly
Show the 3 parameters on the sheet.
Update the 3 entries with a Bike Id and its associated Lat & Lon values (eg Bike Id = 8ec444bc696c2c8837ca0dcad39de819 , Lat = 38.8965 , Lon = -77.0334)
We need to identify the selected bike on the map
Is Selected Bike
[Bike Id]=[pSelectedBike]
Add this to the Size shelf on the bikes marks card. Adjust the sizes so True is listed before False and the sizes are therefore reversed. You may need to adjust the slider on the Size shelf too.
Zooming in to the selected bike
Create a new field
Selected Bike Location
MAKEPOINT([pLat],[pLon])
then create a buffer of 2000m around this (the requirements state 1000m, but I found that there were free bikes that were over 1000m from their nearest station, and if they were clicked on in the grid, the map didn’t display).
Selected Bike Buffer
BUFFER([Selected Bike Location],2000,’m’)
We want the map to ‘zoom’ into this buffer area if a bike has been selected, but show all bikes & stations so we need
Within 2000m
([pSelectedBike]=”) OR ((INTERSECTS([Bike Location],[Selected Bike Buffer])) AND (INTERSECTS([Station Location],[Selected Bike Buffer])))
Add this to the Filter shelf and select True
The map should zoom in, and the bike selected should be quite central to the display (the middle point of the buffer). To verify this, create
Buffer for Zoom
IF [pSelectedBike] <> ” THEN [Selected Bike Buffer] END
Add this to the map as another marks layer, and the circular buffer ‘zone’ will be displayed (we’ll keep this here for now for validation purposes).
Reset the pSelectedBike to <empty> and set pLat and pLon back to their default values – the buffer circle disappears.
Kyle hinted that we need to make sure that on ‘zooming out’ the display should be centred on the default values. To ensure this, we want to create a buffer around that central point that encapsulates all the stations and bikes. So we need
Default Location
MAKEPOINT(38.9358,-77.1069)
Default Buffer
BUFFER([Default Location],30,’km’)
Choosing a 30km buffer was just trial and error.
Now update the Buffer for Zoom field to
IF [pSelectedBike] = ” // then we’re in the default ‘show all’ view THEN [Default Buffer] ELSE [Selected Bike Buffer] END
A buffer zone for the whole display is now shown
Ensure the buffer marks card is displayed at the bottom, reduce the opacity of the colour to 0 and remove any border to make the circle disappear. Then click on the eye symbol to the left of the marks card name to make the map layer disabled, so it doesn’t show up on hover.
Finally adjust the Tooltips on the relevant marks cards and then name the sheet Map or similar.
Building the Bike Selector Grid
To build this we will need to identify the closest station to each bike. First we need the distance between each bike and each station
Distance Bike to Station
DISTANCE([Bike Location], [Station Location],’m’)
and then we can create
Distance Bike to Closest Station
{FIXED [Bike Id]:MIN([Distance Bike to Station])}
On a new sheet add Bike Id to Detail and Distance Bike to Closet Station to Colour. Change the mark type to square. Sort the Bike Id by the field Distance Bike to Closet Station ascending.
Add Lat and Lon to the Detail shelf, and update the Tooltip as required. Name the sheet Bike Grid or similar.
Adding the interactivity
Add the two sheets onto a dahsboard, then create 3 dashboard parameter actions
Select Bike
On select of the Bike Grid sheet, set the pSelectedBike parameter with the value from the Bike Id field. When the selection is cleared, reset to <empty string>
Set Bike Lat
On select of the Bike Grid sheet, set the pLat parameter with the value from the Lat field. When the selection is cleared, reset to 38.9358
Set Bike Lon
On select of the Bike Grid sheet, set the pLon parameter with the value from the Lon field. When the selection is cleared, reset to -77.1069
And with that, hopefully the map should zoom in and out as required, albeit a bit slowly… (gif below recorded on Desktop)
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
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
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]<= 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 bottompTop 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 bottompTop 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.
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
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.
Donna + DataViz 