Wednesday, 26 January 2011

Some graphs relating to OpenStreetMap GB road name completeness

Here are some graphs derived from our service that compares road names in OpenStreetMap with those in the Ordnance Survey's OS Locator product.

This first graph shows how many road names are missing from OpenStreetMap that are in OS Locator with the 408 districts/boroughs organised with the ones with the least missing on the left and the most missing on the right. Do be aware that the size of authorities varies very considerably from the Isles of Scilly with 57 roads to Leeds with 12,000! Clearly there are a small number of larger places with where a lot of work is required.



This next graph shows the percentage completeness of these same authorities. The colour bars match with the thematic map. Nearly half the authorities now have 75% completeness and do be aware that many of the missing road names are likely to be for very minor rural roads/tracks or for small cul-de-sacs in town. As such an authorities with 75% completeness is likely to be very usable for most purposes.


This final graph shows all the 253,000 road names in OS Locator that are currently missing from OpenStreetMap as a cumulative version of the first graph. The most complete authorities are again on the left. It shows that one could complete the 'best' 204 authorities by adding 50,000 roads but to complete the others would need a further 200,000 roads with is a lot of work to do manually.



Personally, I am starting to think about a bot that could add a lot of these roads automatically for the less well covered areas using OS VectorMap District an OS Locator. The bot would do what it was sure about for an area as instructed by a mapper who would then do a cleanup job of the area afterwards.

2 comments:

pingu said...

The tables are slightly unfair on Welsh Authorities because a street is classed as missing if either the welsh or english has not been added. OS randomly give streets welsh names as well as english. The newer streets are always given english and welsh names, but OS only use the english. Probably because they get in information from PAF

Dan said...

Hi - interesting stuff. I don't know who you are TBH but thanks for your analysis - I used it to check where I live in London (almost 100%) and my home town of Burnley... 29%!

I used your tool to help edit Burnley, and I've just got it over the 50% mark which is great. However, while doing this tracing manually it did occur to me that it should in theory be bottable.

I don't know if there are legal reasons not to have bots fill it in, beyond the data quality question. Also, doing it manually gives an opportunity to improve it: as I trace from OS StreetView, I fix connections between roads, fix outlines, add streams and parklands, etc.

Cheers anyway