[Talk-GB] Bristol - a quick (and surprising?) statistic...
richard at richardmoss.co.uk
Mon Aug 2 22:15:39 BST 2010
On 23 July 2010, Tim François wrote:
More info here: http://wiki.openstreetmap.org/wiki/User:Tiiiim#Bristol_-_Missing_Roads
Perhaps the figure won't be surprising to many, but I thought it was pretty large! Is this representative of other similar sized cities/towns? (I know OSL isn't 'perfect', but its better than nothing....)
I was shocked - here in Cambridgeshire, we thought we were getting close to 100% , particularly in the City and South Cambs, so I've had a look at my own village to try and understand what's going on.
On the Royal Mail list of postcodes for the village, there are 46 streets, and in OSL, 10 of them are wrong - i.e. 78% correct, which is a bit worse than the 82.98% figure for South Cambridgeshire given at http://www.itoworld.com/product/data/osm_analysis/
This is a list of the 10 that are wrong:
Name in OSL Name on OSM Comment
Chapman's Way Chapmans Way 2 road name signs, both say Chapmans: OSM correct
Hill Road Mill Road Mill Road is correct
Unwin's Lane Unwins Lane 2 road name signs say Unwins and 1 says Unwin's
High Street High Street (Over) Useful distinction from nearby High Streets in
Swavesey and Willingham, especially when these names
appear in the like of www.cyclestreets.net . I'm not
going to change what has been put on OSM
Station Road Station Road (Over) ditto
The Old Wood Yard The Old Timber Yard Whoops - my mistake. Careless adding of a new development.
Sign says The Old Woodyard (all one word) so both wrong!
I will correct
Whines Lane Whine's Lane There are 2 road name signs. One of each
The Doles The Doles (East) ) OSM reflects signs on the ground. OSL agrees with the
The Doles The Doles (West) ) Royal Mail street list.
Randalls Lane Randall's Lane Street sign says Randall's, as OSM
(apologies if the formatting comes out wrong)
In reality, there's only one error in OSM, and 45/46 is 97.8%. I don't want to get into a debate about apostrophes!
You could then note that there are various farm tracks outside the village which have names in OSL, missing on OSM and not in the Royal Mail postcode list: Long Lane, Ouse Fen Road or Bank, Long Holme Drove, Long Drove. There is no evidence for these names on the ground. Some have been added to OSM from local knowledge: Chain Road, Gravel Bridge Road. Then we are perhaps at 47/52 = 90.4%
So I am heartened. Tim's analysis is very useful in pointing out areas for attention, but the reality is not as bad as the figures suggest.
More information about the Talk-GB