For a long time I've been wanting to produce some numbers detailing the size and growth of our national contributor communities. While a lot of things are sort of assumed to be true for example that the D-A-CH region is by far the largest community we've been missing some hard numbers.
Given the awful weather this weekend I at last had some time to finish off what I had started on a couple of weeks back.
So that you can play around with the numbers yourself and have a look at what interests you I've dumped the output in to a LibreOffice spreadsheet.
Some interesting things that I produced for myself:
The above graph shows new contributors per month for the US and Germany, it clearly shows that the adoption of OpenStreetMap in Germany was very strong early on in the projects life and has essentially continued at that level since 2008. The US on the other hand has a completely different history with the growth rates picking up substantially in 2014. It should be noted that the US is nearly three times more populous than Germany so the US is still adopting substantially slower than Germany at this point in time.
Naturally inquiring minds want to know which community is the largest, no surprise there, it is Germany at nearly double the size of the runner up. But a large population, which is one of the major drivers for the absolute size, is naturally not an achievement. So lets have a look at the contributor number per head:
Again no surprise Austria leads the pack. Note this is a bit unfair in that Vatican City actually has 4 contributors per 1000 population and a couple of the other very small states have higher numbers too, but cutting off at half a million population seems to be reasonably sensible.
Finally how are our contributors distributed over the world:
Two thirds of all contributors are in Europe, again no surprise.
Methodology and Caveats (lots of them)
The numbers are generated from geo-coded (country level) changesets and are current as of September 2015. For each changeset the centroid was determined and that compared to a set of OSM derived country boundaries. Of the roughly 35 million changesets 2 million didn't return a result, aka the centroid was not located in a country (likely over water). The first non-HOT or Missing Maps changeset was used to determine which country a mapper belongs to. Filtering out the identifiable HOT and Missing Maps changesets reduced the overall count of contributors by 8000.
- using the location of the first changeset is naturally a very rough indicator of where a mapper is located and further it naturally doesn't take migration in any form in to account.
- along borders using the bounding box centroid will potentially lead to miscounts
- very large bounding boxes will cause miscounts
- 6000 accounts couldn't be associated with a country at all (aka the initial changeset was in the 2 million that couldn’t be geo-referenced)
- prior to the use of hashtags by the HOT community it wasn't possible to filter out such changesets, as a result the contributor number in targets of HOT activations prior to 2013 should be taken with large grains of salt
- country borders tend to be a bit volatile and you can argue a lot about which continent certain countries belong to.