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Posted by Andy Brown on 23 October 2018
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Finding UK TopoJSON Maps for Power BI Shape Maps
As a break from writing a chapter for our new Advanced Power BI course, I thought I'd put in one place the most useful links I've found for TopoJSON maps.
The Power BI Shape Map visual (still in preview at the time of writing) requires you to supply a custom map using the TopoJSON format, which is an extension of the more common GeoJSON format. Maybe some time soon I'll find the time to write more about this!
Postcode Boundaries
I got these from Open Door Logistics. You can right-click to download a list of either postcode areas or districts:

Right-click on either Areas or Districts.
Here are the shape map keys that the two options give:
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Areas | Districts |
I used this to create this map:

Total sales by postcode area.
It's not a map, but I also found this list of postcode areas useful.
UK Counties
You can get a list of the UK counties from David Eldersveld's GitHub site for TopoJSON files:

You must be on the top-level project to see the download option shown.
Even though you're probably not interested in Venezuela, Peru or Poland, you have to download everything and then pick out the file you want.
When you unzip the files, you should see one called uk-counties.json in an obvious folder. When you download this and set it as the source for a shape map visual, you'll see these keys:

The start of the shape map keys for counties in this map file.
Here's what the counties map looks like in Power BI before you show any data:

The shape map as it first appears in Power BI using the downloaded TopoJSON file.
Parliamentary Boundaries and Local Authority Districts
Martin Chorley maintains a list of UK maps here:

You can choose the level of detail for the map you want to download.
You can then right-click on the link to download your choice:

Right-click to download the shape file you've chosen.
The keys for the map above are less useful:

You'll have to work hard to get your data assigned to the correct keys.
Here's the map above in Power BI, before any data has been displayed:

The maps show up with the correct boundaries in Power BI.
If you're wondering (like me) what a Middle Layer Super Output Area is, apparently it's a geographical unit used by the UK census.