Map choropleth viewer

[trickvi]

Moved from openspending/openspending#509

For a dataset with a geographic dimension, the user should be able to aggregate values over that dimension and then use the aggregated data to display a choropleth map.

The hard aspect of this is having the "right" map, i.e. one that captures all the values in the dataset but does not extend much beyond it. Even worse, the identifiers used in the map for regions must also be found in the data, or an alignment must be made at run-time.

In an ideal case, this would also work for subsets of the data and display an appropriate map to match each query's result space.

Take a look at original issue for comments

[mihi-tr]

@tryggvib just ran into this - thought the jquery.choropleth plugin would do this. Doesn't :/

I do prefer to link to a topojson file (data-mapurl="http://my.topojson") and mention an id column (e.q. wardid).

I'd build this on top of leaflet (maybe also allow to specify a tile-server url) and build coloured polygons.