Displaying cartographic personal data using a library, (e.g. leaflet) and a mapping service, (e.g. OpenStreeMap). (We could user google maps, but why not spread the love a little further?)
Collect polygons using http://www.the-di-lab.com/polygon/ (or some other geo-mapping site - hopefully this one will do that eventually). Add them into var/map.json
Change the map dynamically, (context-menu/right-click). Add,Edit polygons. Add,Edit markers. Combine the functions of sites like www.birdtheme.org/useful/v3tool.html Store the data in PDP with versioning.