I am looking for shapefiles of city boundaries for several German cities (possibly including district boundaries within a city). No other spatial information is required. Do you know where I can download this data from?
The research for which I am searching maps started a earlier and does not relate to COVID-19. It is about green spaces and biodiversity.
Are you aware of SIMSOC community? There are quite some discussions related to COVID-19 modeling at the moment (https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=simsoc - to subscribe).