As mentioned in my previous blog post about detecting vandalism in OpenStreetMap (OSM) edits, it’s highly recommended that contributors use public changeset discussions when contacting other mappers regarding their edits. This feature was introduced at the end of 2014 and is used widely by contributors today. Each and every comment is listed publicly and every contributor can read the communication and, if necessary, add further comments or thoughts. In most cases where questions about a specific map edit come up, it is desirable that contributors take this route of communication instead of private messaging each other.

For my presentation at the German FOSSGIS & OpenStreetMap conference I created several statistics about the aforementioned changeset discussion feature. For this blog post I reran all analyses and created some new charts and statistics. Let’s start with the first image (above): It shows the number of commented or discussed changesets per month since its introduction. The peak in January, 2017 is based on a revert with several thousands of changesets.

In total, more than 92,000 changesets have been discussed in the past few years with around 151,000 comments. All comments were created by almost 14,000 different contributors. So far most changesets were commented in Germany, the United States, Russia and the UK, as you can see in the following images. This correlates to some extent, with the exception of Kazakstan, with the number of active contributors for each country (see e.g. OSMstats for active contributors). As shown on the right side, many changesets (71%) only received one comment or discussion. This means, in most cases the commented changeset did not receive a response by the owner/contributor of the changeset.

Which changesets are discussed and who creates comments? I think it’s not surprising to see that most changesets by new contributors receive a comment. However, as the following charts show, there are also changesets by long-time contributors that have some discussions. It’s also quite interesting to see that all kinds of contributors (new and long-time) created discussions. I would have expected a trend towards contributors with a higher number of mapping days.

What is the origin of the contributor who created the comment? Again, not surprisingly, this correlates with the number of active OSM contributors per country as mentioned above. The contributors’ origin is determined by his/her main activity areas which you can find/see on “How did you contribute to OpenStreetMap?“.

Some additional numbers about the text content of the changeset discussions: Roughly 22% of the changeset comments contain the word “revert”. On the other side, more than 17% include some sort of “Welcome”, “Willkommen”, “Hello”, “Ciao”, “Hola”, “Bonjour”, “nǐ hǎo!” or “привет!” text. The following image shows a word cloud of the most used words in the changeset discussions:

The last chart shows the accumulative changeset discussion contributors and comments. Almost 63% of all discussion comments have been created by around 2% of the contributors. However, I assume this looks very similar to other long tails of OpenStreetMap contribution charts. What do you think?

Want to see the latest OSM discussions in your area or country? Check this webpage.

Thanks to maɪˈæmɪ Dennis.