Last week I was able to present a variety of statistics that showed the amount of OpenStreetMap (OSM) members of the database compared with the numbers of  the actual amount of registered members.  However, I was just able to consider the most recent dataset (Planet Dump 08/19/2009) and could not take the history of the different objects into account. The results of this first analysis showed that last changes in the OSM database have been made by a total of 98.000 members.

In one of the comments to this post, Apmon mentioned that he had conducted a pretty similar analysis in the past but he had used the changeset file. In his case the results showed about 130.000 members that had contributed to OSM.

For a couple of months now there is a, for now still experimental, full planet dump file available, which also considers the history of the OSM objects. I repeated my analysis from last week with this dump file and counted all the members that ever created a node, a way and/or relation or modified any of them. The results showed about 112.000 OSM members.

I was still surprised by the differences between the results of my analysis and the one conducted by Apmon. So I took a closer look at the changeset-file. Using the most recent changeset-file (08/25/2010) I received a pretty similar amount of almost 132.000 members that assumedly made changes in OSM. However, the results show that there is a noticeable difference between the changeset-file and the planet-file. But where does this difference come from? Could there be changesets that have been recorded although nothing has ever been changed in the OSM database? Apparently the answer is “yes”! The number of members in the changeset file that caused a changeset but never included any actual changes is around 16.000. I asked Frederik how this could be possible. He and Matt explained that as soon as a member signs in with Potlach a changeset is created automatically for this user. This means that 16.000 members signed in with Potlach but never made any changes in the database? Very interesting number, isn’t it? Did the “new” members only take a look at the editor or were they overstrained?

By Damien Cox

There was another comment to the last post by Harry, who suggested, to send an email to all OSM members, for example afterfinishing Potlach 2. This way the “non-active” members might get active and interested in the project again. I think this is a great idea! Although there are a few things that need to be considered before doing this, as Harry mentions in his comment …

… and again: thx @ dennis !