Custom geojson data in legacy-plugin-chart-country-map

[luca-vercelli]

It would be useful to allow custom GeoJSON data in the "Country Map" plugin.

For example, I have a GeoJson file for Piedmont, a region of Italy, split into "comuni" (an administrative division in Italy, where a "comune" represents the municipality/territory around a town).
I have arranged it so that it successfully works inside a Country Map.

However, I don't think it is a good idea to include this map in the standard built-in Superset maps, because

1. there would be thousands of similar maps around the world
2. the same region could be split in different ways (for instance, "comuni" and "province" are two distinct types of administrative divisions)
3. a "comune" does not have an ISO 3166-2 code; we use our own codes.

So, an option would be to let users choose within the plugin: either use one of the standard maps, or provide a custom one (perhaps via a URL or a local file path)

What do you think about this?