[Talk-GB] Ordnance Survey
david at frankieandshadow.com
Mon Apr 5 17:44:31 BST 2010
I thought it was very interesting to look at the OS and OSM overlaid on
each other on the WMS link someone posted.
1. I was very impressed with how really accurate OSM is compared to OS
where I know it has been done systematically
2. I was disappointed to see how out of date the OS data is - streets
which I know personally have been there for two years still aren't in
the OS data - but it's not all that out of date, some recent streets are
3. OS street detail has some real problems where a street is closed off
part way along - streets where there is a bollard or a section of
footway between street ends look like they are continuous streets on OS
where I've looked (maybe this will be better in the vector stuff to be
released). No wonder we get these tales of trucks following satnav only
to end up stuffed.
4. I'm disappointed how many street names are missing on OS, especially
short ones (short street not short name).
Mapnik is a much prettier rendering as well, IMO.
While I agree with Tom and Jonathan about tracing putting people off
doing the base level survey, I have found that where the basic street
level survey has been done properly, people will make small corrections
from local knowledge and quick checks and surveys, where they aren't
prepared to spend a whole day doing something. Quality has improved in
most areas I've done over time (though it's still clear to me that we
are very poorly represented in very rural villages).
I'm not sure tracing is quite so problematic as from satellite, because
OS has street names as well, but someone is still going to have to go
back and get detail and check it (otherwise what is the point - if all
we are going to do is trace OS, the user might as well use OS in the
I think one of the problems of this completeness is people don't know.
Now I know Harlow needs attention I might well put it on my list for a
visit. We did that for King's Lynn where we had the street pattern but
no names and no other detail (though we've not finished yet), but only
because I looked carefully at what had already been done.
Personally I don't see the attraction of just sitting for hours in front
of a computer duplicating someone else's product. For me the interest in
OSM is the exploring, the wind in my face, the exercise. I think it's
actually a shame that if people start tracing everywhere we can't say
this is the fruit of our own labours. I'd still really like to complete
Cambridgeshire by surveying. At 93%, we're so nearly there, and I'd
really like to be able to say yes, *we* did it.
Where I think I'll use the OS base most is if I miss a street name by
accident, and will save going back to check it. But poersonally I won't
be spending yet more time at my computer mindlessly copying.
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