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The Missing Mappers Problem?

Posted by dalek2point3 on 2 July 2014 in English. Last updated on 3 July 2014.

While playing around with the changeset data I noticed an interesting pattern. There were some users who had made a lot of contributions to the map, who were nowhere to be seen. A lot of the talk in the community has been on attracting new mappers, but if we’re losing existing mappers that is surely a problem, no?

Wondering if this was a big problem, I decided to dig in. Here is what I found – it doesnt seem to be a HUGE problem at the very top, but there are many mappers who make 10 or 100 changesets that never come back. Note that this is only using data from the USA at the moment.


First thing to notice is the blue line – these are how many users there are for a minimum number of changesets. 44k users have more than zero changesets, 25k have more than one changeset, 100k have more than 5 changesets and so on. There are only about 273 who have more than 1000 changesets, and I’ve done my best to get rid of imports so these are likely to be real people, but Im sure a few of these include imports.

Now, how many of these users seem to be lost from OSM? The Orange, Yello and Green bars plot number of users who have not made a single edit within the US in since 2012, 2011 and 2010 respectively. So, for example, looking at the extreme right, of the 273 users who made at least 1000 changesets, 22 have not been seen since 2012, 12 since 2011 and 4 since 2010. The problem is a little bit more acute if you looked at those who made at least 500 changesets. Of this group, about 50 have not been seen since 2012.

Who are these users? And why did we lose them? Was it due to contributor terms or is it just bots which are no longer being deployed?

Here is the list of the top missing mappers that I could find in my data, heavy mapper that have not been seen since 2012! Chime in, in the comments if you have any theories about where these lost souls might be and what we can do to bring them back!

Here at the top 10 users who have at least 500 changesets and have not been since since 2012:


Click here to check out the full list!

Location: Lechmere Square, East Cambridge, Cambridge, Middlesex County, Massachusetts, 02214, United States


Comment from CraigRat on 3 July 2014 at 03:39

For me it was the license change/redaction. Not because of the new terms (which I agreed with) , but the hundereds and thousands of edit I had done prior to the redaction were lost due to being on the back of data laid down by people who didn’t accept the new license. It was a gut-busting blow to see so many long hours of work go down the drain, and I was not prepared to do it all again, just in case we have the same thing happen again.

I know I am not alone in this.

Comment from SK53 on 3 July 2014 at 09:20

At least 2 of these are active mappers (brianboru mainly maps in Birmingham, England and was lead organiser of sotm-13, SK53_bulk is an import account which I used to for NHD data for the Upper Colorado Basin). There may be other mappers from Europe who contributed to clean-up of the interstate system around 2009.

Comment from SB79 on 3 July 2014 at 09:39

Thanks for that. :-) This is quite interesting.

Regarding your first figure: it might be interesting to learn whether the percentage of people who leave OSM did indeed change over time. To be honest, that might be a tricky thing.

It might be, for instance, that the increase in numbers of non-returning users does simply reflect different sample sizes: there were not so many registered users in 2010 as in 2012. So the “potential” number of non-returning users is larger in 2012 than in 2010.

Some kind of normalization with respect to the total number of users registered at the point in time where users left OSM would be interesting to visualize. For instance you could divide your numbers by the respective total number of registered users in 2010, 2011, 2012. That way we could (maybe) learn whether there are specific periods in the history of OSM during which more than the usual percentage of registered users left OSM.

Comment from Warin61 on 3 July 2014 at 10:43

Some may have spotted something they can contribute in there local area, once done they leave. Nothing wrong with that, they may come back when they travel some and see something else to change.

Comment from BlueTiger on 3 July 2014 at 14:14

@dalek2point3, interesting information.

Some information about my contribution pattern:

  • I joined OSM sometime in August 2012 and started editing my neighbourhood. Places near my home were mapped pretty quickly and then came a lull period as most of the places I frequent were already mapped.

  • At times when I have nothing else to do, I do some armchair mapping. Mostly tracing roads using Bing Sat images.

  • Most of the times when I travel I will leave the OSMTracker running and update new POIs. At times I have skipped uploading POIs as they don’t have proper tags in OSM. Unfortunately I have taken a bad choice here, I should have updated them anyway and requested for new tags.

Why I contribute to OSM? : I am a big fan of Open Source Software and Open Data. I am impressed by the range of data OSM can capture about a POI, which can be used in many useful ways.

How did I join and ended up contributing to OSM? : I wanted an off-line map/navigation software for my Android phone and the application which I used first happened to use data from OSM. Once I saw that I could contribute to the OSM, I was hooked.

Will I continue to contribute to OSM? : Looks like I will continue to do so for the foreseeable future.

I think it would be a good idea to initiate a survey among OSM users once you get some basic information from here.

Comment from mvexel on 3 July 2014 at 22:03

Thanks for sharing these insights!

Comment from Rovastar on 3 July 2014 at 23:58

Nice graphs.

However do not think this is bad at all.

You seem to have users with >500 changes = 490 (probably could reduce this for bots,imports, etc you found) and only 49 people have dropped out (with the bots, imports removed). Percentage wise that is really low about 10%. As as others have pointed out some are from Europe and are still continuing but not in the US e.g. as above and randomly checking a couple of them , there is at least another bot in there too ( So it could be lower still maybe overall 8% or something. That I think is pretty good.

It will never be zero.

Obviously you would like it to be people move on to different things in the life and not contribute. (I am sure we have all done than on things in the past). Others sadly will get ill (or worse) and cannot continue contributing.

As long as the the numbers of contributors increases more than others drop out it will keep getting better.

Comment from pitscheplatsch on 4 July 2014 at 04:28

right, you’ll find some similar results here: “Recent Developments and Future Trends in Volunteered Geographic Information Research: The Case of OpenStreetMap” (Open Access) [1] Page 88 Figure 3 [2].

[1] [2]

Comment from smsm1 on 4 July 2014 at 21:05

According to I’ve made 67 change sets in the US so far. As I haven’t visited or had reason to edit in the US recently, it’s likely I’ll be one of the “missing” users. Could you re-run the stats worldwide to see how they compare?

Comment from Jacques Dupoint B on 6 July 2014 at 11:35

Thanks for the share ;) it’s very interresting !

Jacques de

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