The map shows the the administrative areas in which the defined community has nodes even if they are offline. To use this software you need the d3map backend nodes.json file or the meshviewer nodelist.json file. This script querys the mapi API. This is an API provided by the mysociety for low frequecy querys, so please only query one or two times a day. I'm sure your areas doesn't change that often. https://github.com/mysociety/mapit
But to mitigate this we now have a great caching mechanism.
./mkpoly -f nodelist https://map.darmstadt.freifunk.net/data/nodelist.json
./mkpoly -f ffmap http://map.ffrn.de/nodes.json
./mkpoly -h