[Talk-GB] Ordnance Survey

David Earl 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 I was disappointed to see how out of date the OS data is - streets 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the OS data - but it's not all that out of date, some recent streets are 
there.

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 
first place).

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.

David




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