Andy Allan wrote: > On Thu, Apr 10, 2008 at 12:52 PM, Lester Caine <[EMAIL PROTECTED]> wrote: > >> But that only addresses one small 'problem' and misses the bigger one of >> finding 'all the golf courses in England' or 'all the Islands in the >> Philippines'. A single lookup to find ALL the boundaries you are currently >> looking within is probably not a major overhead, but the reverse search is >> going to involve potentially hundreds of thousands of such enquiries? > > No, you're completely wrong about "hundreds of thousands" of queries. > "All the golf courses in England" is fairly trivial for the database > to calculate when there is an index on the leisure column (so it's > lightning to get all the leisure=golf_course polygons) and then > selecting those that are in the "England" polygon (using the spatial > indexes to compare the bounding boxes of the polygons). It's what > indexes are for - there's very little processing involved. > > Honestly, it's much simpler and much faster than you think.
However, but looking up a number of locations using the 'Where am I?' button and the key intermediate information is missing. So how do we ensure that the information is at least available. I had Naga up on the may, and Where am I? vaguely points to the Philippines but misses the Island or area that it is in. I've done a search for Broadway United Kingdom and I get 5 results in five different counties, but all are listed Broadway, United Kingdom and I have to select each to find the one I want. What is needed to make the intermediate hierarchic data available? SO I can find Broadway, Worcs, UK :( -- 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 [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
