Tuesday 2 February 2016


People meet up in a few areas across Britain drawn together to share views and ideas about OSM. One of these is known as Mappa Mercia, meeting in the old Kingdom of Mercia, roughly the Midlands. They started a quarterly series of projects which encourages people to focus on improving specific areas, such as nature reserves. This quarter it is schools.

People across Britain have taken to the suggestion of checking schools and improving the quality of recording schools. This is a simple idea that will greatly improve the quality of data in OSM, something that the quarterly projects have always aimed at. It's a great idea and something I support.

There is a list of UK schools available as open data which Robert has used to show a map of how well the schools in the list are represented in OSM. It uses postcode areas as that is how the open data is structured. This is a very good indicator of areas that still need work.

This is all useful, but then I think the project took a wrong turn. People were encouraged to add a hashtag to changeset comments. This has then been used to produce a list of people who have contributed the most changes to the project. I don't like this. OSM is not a competition and turning it into one encourages edits just to climb the list (I'm not accusing anyone of that, just that the pressure is created). We have seen that with the list of anomalies published between OS Locator road names and OSM road names. To push an area up the list people just use the OS Locator names without checking. I know that OS Locator contains errors and there is a mechanism to record these, but many areas have very few recorded errors, so erroneous OS data is now in OSM.

I like the idea of focussing on improving specific things in OSM. It should encourage surveying. I would prefer it is not be seen as a competition.


vdp said...

We have a similar problem with Irish townlands, a daunting multi-year task with a great website (townlands.ie) to track progress and use the data, but also a contributor list sorted by townland count (at least it's not based on a hastag in the changeset comment :p please stop using those).

Some of those are traced with low precision, with no improvement after contacting the guilty. Some mappers are now even considering recreating badly-drawn townlands rather than simply improving them, so that the original mapper doesn't get the stats credit. No fun.

That said, I feel that the outcome of the contributor stats is generally positive, and is good to have. Most contributors do good work, and the ranking page has helped attract contributors for this herculean task.

Unknown said...

I don't know whether ranking is the only reason why people do not pay (enough) attention to detail.

I recently noticed something similar in the address import in Flanders. We still have to draw the houses from aerial imagery. There is no ranking kept, but some people just draw simple rectangles for the houses (while the quality of the images allows one to add almost all extrusions). Of course this is way faster than drawing detailed buildings, but is it better ? Why do they do this ? Laziness ? The idea that a rectangle is good enough as long as the address data is there ? I don't know.