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 ----------------------------- Contact - http://home.lsces.co.uk/lsces/wiki/?page=contact L.S.Caine Electronic Services - http://home.lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk// Firebird - http://www.firebirdsql.org/index.php _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk