google mapsordnance-surveypolygon
I'm working on a web project that requires polygons and lat/long coordinates for the boundaries of towns, cities, counties, and postcodes.
Does anyone know where I can obtain this data?
I know rightmove has it, but can't figure out where they get it from.
One approach could be to use OpenLayers to enable users to draw polygons onscreen, and then to store these polygons in a postgresql/postigs database, transferring the data using the WFS-T protocol. I would avoid using the Google API directly as it does not easily facilitate analysis.
I don't quite understand what you mean by 'non-overlapping polygons'; do you want users not to draw over existing polygons?
What you are requiring sounds like Map Channels (v4) or MapFab
It's Simple you sign up and load your data from Google Spreadsheets in and you can edit/filter data. This does not edit data directly with the map.
http://www.mapchannels.com/MC4Demo.aspx
If you want edit data directly on the map I suggest: MapFab
http://www.mapfab.com/editor/new
(both use google ads to generate the income.)
Best Answer
For administrative boundaries, GADM is always the best free source:
http://www.gadm.org/download
adm_2 includes the counties and larger town boundaries.
If you need more, have a look at what Ordnance Survey offers as OpenData:
http://www.ordnancesurvey.co.uk/business-and-government/products/boundary-line.html
For the post code data (which is not published freely), see http://wiki.openstreetmap.org/wiki/WikiProject_UK_Postcodes