Pie chart Illusion on a Map

Power BI gives us multiple ways of visualising Demographic based data by imparting multiple map visual capabilities. My personal favourite map visuals are – Map visual & ArcGIS map. The reason for they being my favourite is that in most of the real-world scenarios I can use these maps to represent the information in self-explanatory way. Today, in this blog we will take a small use-case to represent the categorical information on a map which gives the pie-chart illusion on the map visual adding a split down the further level. Just to highlight - it is a pie-chart view on the map visual, not plotting an actual pie-chart visual on a map visual.

For explaining this use-case, I will take “Retail Analysis Sample” report from Power BI which is freely available to download as a pbix file from the following link: https://docs.microsoft.com/en-us/power-bi/create-reports/sample-retail-analysis#get-the-pbix-file-fo...

This report has got pre-created visuals for example, the 1^st tab (“Overview”) on this report gives a summary on Store sales:

The map visual at the bottom is interesting as it shows the sales split by store type (New vs Old) by postcode:

The map clearly shows me which are the new stores and how much sales they have generated by different postcode areas.

Now suppose I am interested in knowing what all sales different item categories at these stores are generating. What I do to achieve this is under Legend section of this map, I move “Category” column coming from the ITEM table and get the following map visual:

Can you see the beautiful pie which are generated by showing us the split of these sales by different item categories? In a way these really help in understanding the proportional sales split. Like we can clearly see that the Category shown in YELLOW (Home category), shows it’s sales split at the postcode area when we hover over it.

I like the fact here that the illusion of the pie-chart over the map, gives the clear distributional sales value at the item's category level and gives user a clear picture on which categories are generating the most sales. This insight can even help the marketing team to target the items that are not generating huge sales in different postal areas and may want to run further analysis on finding the root cause of this sales difference.

I came across this hack while working on one of the reports and thought of sharing it.

Let me know what your view on this simple hack is and hopefully this simple analysis helps everyone.

- Pragati