[OSM-talk] Naga City in OSM Re: GML to OSM
lester at lsces.co.uk
Thu Apr 10 11:13:39 BST 2008
Andy Allan wrote:
>> Something that has already been discussed is an information box for the corner
>> of a map with reference data, but without information accessible quickly from
>> the data how do you populate that box? Cached data on a tile by tile basis may
>> be possible, but it still requires access to the raw data in the first place
>> and having to search a large adjacent area just to find a country name is
>> silly when a properly managed is_in would return it in the one database query?
> I'm guessing you don't have any experience with spatial databases?
> bool ST_Contains(geometry_of_polygon, geometry_of_point) and so on?
It's because of my experience that I'm looking to reduce the number of such
queries when - for example - you are trying to find all of the properties in
Worcestershire. I have access to a number of LLPG databases, and while it is
not yet possible to upload them - because of OS and other licences - I can see
a point in the future when the NLPG database WILLl be available at which time
we will have a step change in volume data available for the UK including every
alley-way, public footpath and piece of land. At that point I don't think I
want to even consider processing 10's of millions of polygons simple to
establish which ones are in a certain area.
Lester Caine - G8HFL
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