Another round of Ordnance Survey data has been released and processed by ITO! to produce a very useful comparison against OSM. Once again, their very usable web slippy map, and JOSM layer this has shown up a new building site I didn’t know existed ready for survey.

ITO World Open Data Tools

As well as missing developments, the comparison also showed up a fat-fingered typo from one of my past surveys - quickly fixed!

As usual, don’t assume OSM mappers are any better or worse than the professionals - OS data feeds from local authorities don’t always match the ‘ground truth’ signage and so don’t accept the OS Locator data has to be correct without a check particularly if OSM is marked source=survey.

If there’s no signage out there to contradict or correct, then an attributed name from OS is better than none (source:name=OS Locator). If Locator is wrong, use the tag ‘not:name=’ to show the issue to comparison sites like ITO, and also to OS so they can check themselves.

So once again, raise a glass to OS Open data, ITO for the service, and the local groups of fellow mappers slowly increasing the comparison UK Percentage Complete beyond the current 97.60%.

Help turn all UK counties UK cyan on the overview map - a 100% match!