Last year I wrote two blog posts about the OpenStreetMap (OSM) feature that allows commenting on contributor map changes within a changeset. The first blog post showed some general descriptive statistics about the number of created changeset discussions, affected countries, the origin of the commenting contributors or their mapping reputation. The second post described a newly introduced feature, where contributors can flag their changeset so that their map edits can be reviewed. This blog post will follow up on this topic and conducts some similar but updated research.

The first chart shows the number of created comments (discussed changesets) and the contributors involved over the last 15 months. The number of created comments and discussed changesets fluctuates over time, whereas the number of contributors who take part in changeset discussions stays consistent at around 1,500 per month. Around 3,200 contributors received a comment on at least one changeset’s map edits a month.

After publishing the aforementioned blog post, people were asking for some numbers that show the commented changeset grouped by the editing application that was utilized. The results show that these numbers stayed more or less the same with 2/3 of all commented changesets (almost 160,000) being edited by the iD editor. This is not very surprising since this particular editor is used by many OSM beginners during first edits. It’s also interesting to see whether the changeset author responded (also grouped by the OSM editor that was used). Overall only around 32,000 contributors responded to their changeset comment. You can find some additional charts about the comments per discussed changeset in the previous blog post. Again, the majority (around 71%) of the changeset discussions contain one comment only.

Since last August, contributors can mark their changeset with a flag for “review_requested”. After a few months now I think it’s time for a first look at the numbers. The following charts display the number of requested reviews by contributors and their marked changesets. First of all, almost each month around 7,000 contributors asked for one review minimum. Overall almost 36,000 changesets have been marked for review each month. If we take a close look and filter changesets by hashtags, we can see that sometimes large numbers of the changesets are contributed by #HOTOSM or #MissingMaps members.

The following diagram shows probably the most disappointing results: The number of requested reviews that actually have been reviewed in the end. No matter if the changeset has the #HOTOSM or #MissingMaps tags or not, the relative value of reviewed changesets lies only between 6 and 18%. To be honest, I’m also a bit surprised that only a few of #HOTOSM or #MissingMaps changesets have been reviewed so far.

So, what do you think? Do you review contributions without commenting on the changesets? Do we need more attention here or is it just boring to look after changesets which are marked for review? I think it’s obvious, that we need more contributors who review map changes or least “documenting” their work. But can we handle this? Or do we need better tools?

Thanks to maɪˈæmɪ Dennis.

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.