Hello again, I found the generate_series function (yes i am a newbie!) and I can use it in order to calculate the distance between my centroid (geometry_centroid) and my polygon (geometry_zone) with the following request
SELECT (distance_spheroid(geometry_centroid,ST_AsText(ST_PointN(ExteriorRing(geometry_zone), generate_series(1,(SELECT npoints(geometry_zone) FROM "208_1_26624_zones" WHERE "cellID"='1')))), 'SPHEROID["WGS 84",6378137,298.257223563]')) as d FROM "208_1_26624_zones" WHERE "cellID"='1'; Now I can't use the max function because of the following error: "set-valued function called in context that cannot accept a set" when I use SELECT max(distance_spheroid(geometry_centroid,ST_AsText(ST_PointN(ExteriorRing(geometry_zone), generate_series(1,(SELECT npoints(geometry_zone) FROM "208_1_26624_zones" WHERE "cellID"='1')))), 'SPHEROID["WGS 84",6378137,298.257223563]')) as d FROM "208_1_26624_zones" WHERE "cellID"='1'; any idea ? thanks! Nick 2009/2/18 My Pid <[email protected]> > Hello, > > I would like to know how I could get the maximum distance between a POINT > and a POLYGON. > (the POINT i am talking about here is in fact the ST_Centroid of the > mentionned POLYGON) > > I looked for a function that transform my POLYGON into several POINT but > without success. > > I am working with longitude, latitude, altitude for POINT > It is really the max distance that I am looking for (not the minimum > distance.) > and "accuracy" is important to me. > > thanks in advance for your help ! > > regards, > Nick > > >
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