Hi all I've a load of point data i'm storing in SRID 4326. I want to do selects using ST_DWithin(a,b,distance) where the distance is in meters so clearly I need to transform the a and b geometries to some SRID thats meter based? Can anyone suggest what i should use? The points are located all over the world (hence a UTM zone might not be suitable? perhaps World Mercator 54004?) but the actual DWithin distance will never be more than 20KM.
Also, I want to calculate the actual distance between geometry a and b as part of the select, I suppose using ST_Distance_Sphere is my best option? The precision isn't a major factor. Errors of up to 200M over a real distance of 20KM are acceptable for the solution. Will ST_Distance_Sphere suffice or should I move up to ST_Distance_Spheroid? Many Thanks! Garrett _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
