Matt's Blog

OSM Without Delay – SotM10 Talk

I gave a talk at State of the Map, OSM’s annual conference, about the minutely diffs; why they should be used, a little introduction on how they could be used and some examples of things that already use them. I also used the talk to advertise the OWL system I’ve been writing.
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2 comments July 12th, 2010

Editor retention

I’ve been playing with the changeset data for OpenStreetMap and looking to see what patterns I can find in the usage of various editors since changesets were introduced in the API 0.6 migration. We can start off just looking at the major editors by distinct users, i.e: everyone’s favourite popularity contest.
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11 comments December 4th, 2009

Imports and the Community II

Thanks for the feedback on the previous post on imports; it got me thinking about whether my model had been over-elaborate. Specifically, the limit on the model agents which capped the maximum “completeness” levels at which they would contribute. I thought this was a necessary part of the model, but after investigation it turns out it isn’t.
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September 10th, 2009

Imports and the Community

I’ve been thinking recently on the effects of imports on the OpenStreetMap community. But there’s no real hard data — and repeatable experiments would be difficult if not impossible. So I’ve turned to that old “what if” machine; the Monte-Carlo simulation.

A caveat before reading the whole post: I’ve no way of backing any of this up, so treat it as an “informed guess”. There are assumptions about the dynamics of the community which I’ve used in the model which may, or may not, be true in reality.
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7 comments September 6th, 2009

Editor popularity II

Just for fun, here’s an animated one:

Each frame shows the majority editor in each pixel over a moving 7-day period starting at the date in the lower left of the frame.

August 30th, 2009

Editor Popularity

A while ago, I made a visualisation showing which were the most widely-used editors for OpenStreetMap. This was based on the created_by tag, which isn’t an ideal way to do things because different editors treated that tag in different ways. Since the API 0.6 upgrade, there has been a better method: changesets.

Each pixel is coloured by what proportion of changesets intersecting that pixel were uploaded by that editor; red for JOSM, blue for Potlatch and green for Merkaartor. Don’t read too much into it, though, as the editors have different behaviour when opening and closing changesets.

4 comments August 29th, 2009

Some Changes to OSM: Technical Details

I haven’t updated this blog in a while because I’ve been hard at work on some very important changes to the OSM server stack. Have a look at Steve’s announcement for the high-level vision and continue on here for the low-level techniques we’ve used to speed the server up by at least two orders of magnitude.
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1 comment April 1st, 2009