Comments on: Constituency maps in under a minute

By: Matthew Somerville

Matthew Somerville — Fri, 30 Jul 2010 15:30:53 +0000

No, I'm afraid we don't have boundary data for Northern Ireland, only Great Britain, so any request for a KML file for a Northern Ireland boundary returns 404 "No polygons found". The postcode lookups for Northern Ireland are done using ONS point data.

By: Dave

Dave — Wed, 28 Jul 2010 13:34:13 +0000

Total novice, tried this and the Northern Ireland constituencies don't work (I;m just substituting the 'id' number in the .kml link and pasting into google maps

By: Ryan Cullen

Ryan Cullen — Tue, 27 Jul 2010 15:36:54 +0000

In theory using this should build a map for Rugby
http://dev.artesea.co.uk/maps/?parent=2459
however it's not filling in the boundarys, but clicking on the map will bring up a popup for the ward (might be too many KML files).

Also I'm struggling to fill the wards in with other colours, from what I can see the Google API doesn't allow you to edit the KML data after it's generated.
A possibility would be to store a local copy which had the colours edited in to them, but this wouldn't work as a dynamic option across the country.

By: Ed Trelinski

Ed Trelinski — Tue, 27 Jul 2010 14:14:34 +0000

Thank you all for your assistance. This thread is very close to going way over my head! Ryan makes it appear ridiculously easy. Any chance you can package this is a format I can adapt easily?

By: Ryan Cullen

Ryan Cullen — Tue, 27 Jul 2010 14:10:47 +0000

With 9 lines of PHP and 27 of HTML I've done this for Lincoln in a couple of minutes.
http://dev.artesea.co.uk/maps/
Doesn't have labels or colours, but you can see the boundaries.

By: Simon

Simon — Tue, 27 Jul 2010 14:08:30 +0000

The trouble is Matthew, there's 'quite simply' for you, and 'quite simply' for the rest of us!

KML is basically just XML... so you might get away with downloading the individual files for each ward, then manually merging them, putting them on a web server somewhere, then 'searching' Google Maps for the URL of the merged file.

This example on Google's KML Reference page seems to show how you can then define a set of styles for the various polygons.

This is probably enough to bring a 'proper' developer out in a rash.

By: Ed Trelinski

Ed Trelinski — Tue, 27 Jul 2010 13:55:13 +0000

I've figured out how to display an entire council district, such as Rugby Borough Council, but I want to be able to display all the wards in that district, in different colours, side by side. My technical knowledge is pretty limited on this front so any help would be gratefully received!

By: Matthew Somerville

Matthew Somerville — Tue, 27 Jul 2010 13:52:09 +0000

"Note - these will produce nasty-looking data files, rather than pretty HTML lists." - yes, it could be improved in this regard. Here, have an HTML lookup by type: http://mapit.mysociety.org/areas/WMC.html But I don't think I have the time to do them all; perhaps someone will come along and patch the code for me

Ed: You can add multiple KML overlays to a Google Map using their API quite simply: http://code.google.com/apis/maps/documentation/javascript/v2/services.html#XML_Overlays - this might do what you want.

By: Ryan Cullen

Ryan Cullen — Tue, 27 Jul 2010 13:45:51 +0000

Ed, using the full Google Maps API you should be able use multiple wards, and using the MaPit API you could make it pretty simple just requiring the Parent ID for the county / district.
As it's been years since I've had a play with Google Maps might give it a try tonight.

By: Ed Trelinski

Ed Trelinski — Tue, 27 Jul 2010 12:24:44 +0000

Thanks for highlighting this Simon. I've been waiting for an easy-to-use political mapping tool for ages. Do you know if you can highlight groups of county or district council wards on the same map?