Finally, after weeks of deliberation and numerous conversations, on-line and off, I think I’ve found a satisfactory solution to my long-standing question: how do you build collaborative maps online in realtime using open source software? The one word answer, geojson.io, is contained in the map below. A more detailed answer is provided below.

This problem emerged for me when I move to a new city and wanted to help out their equivalent of Abundance. Now, if you plan on collecting food in a city, even if you think you know it well, you will need maps. Fine you say, just edit Google Maps or create your own paper one. Unfortunately neither solution is acceptable: one’s too social (and the data is controlled instantly by Google) and the other is too antisocial. We want collaboration!

Various alternatives

After a while of searching I narrowed-down my options to the following:

  • Do it in GeoServer, the open source multi-purpose map server. This would be blatant overkill for small community solutions (although it’s one to bear in mind if community maps ever need to join up and scale).
  • Use some kind of 3rd party to host the data, such as MangoMap or QGIS cloud. Each of these solutions were attractive in one way or another but didn’t offer the mass editing or horizontal organisational structure I was after.
  • Manage the geodata files in my favourite version control software Github, taking advantages of the recently added ability to display .geojson files in an overview map. This would be great if I was working with a team of crack coders, but it’s simply too tricky to expect people to edit these files then upload them back up to github from the command line.

Weeks after asking this question to the OSGEO community, I returned to rediscover the following little comment under my original question:

Would add Tilemill to the list At the time this seemed like one option too many, so I gave up. But when I actually found out who was behind TileMill, the web mapping wizard outfit MapBox, I decided to try again.

Discovering geojson.io

It was thanks to direct communications with MapBox developers, not the TileMill solution itself that led me to geojson.io. This software has only been available for a month or so: still rough around the edges. Yet it offers speed, stability and, crucially, the ability to visually edit .geojson files online and save them to existing GitHub accounts. To make the mapping a community project, all that’s needed is a Github team, and anyone in that team can add to the map. If it needs to be private, that can happen too, via bitbucket

Polishing it in MapBox

This is the final stage, to be approached after the map has actually been completed. But given that MapBox specialize in making beautiful maps this should be the easy part.