How to create simple map for cartogram and use it with Tableau

We often want to display some information on a map, but that it is in some other form, eg as part of a diagram or cartogram.

For this procedure I will use QGIS with GRASS. It is an Open source solution, with great features!
In this example, I will use data on the counties of the continental part of Croatia.

One of the problems of quality generalization lies in the fact that if we throw out points on a common line between 2 polygons, there can be an overlap of polygons or holes between them. That’s why I use QGIS.

As a result, we get a simplified view of the polygon.

After that, just make line from polygons, and nodes on polilines, and extract to CSV.

Now that we have CSV for the lines and CSV with the coordinates of the points on the lines, we can use Table Prep and merge the data.

Let’s open Tableau now, and arrange the data according to the rules of connecting lines and polygons!

And that’s the whole story!
Enjoy!

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