> Thanks for the response. A follow up question: what if the yourLongitude, > yourLatitude values provided in the query are not grid points in that they > fall > within a bounding pixel grid. Only values for the intersection points are > known > so how does a non-intersecting point get assigned a value from the query?
Point outside the area covered by the grid are assigned NULL. There is not inter- or extra- polation done. I forgot to mention that if you tile your input raster then you should add a WHERE clause: SELECT ST_Value(rast, ST_Transform(ST_SetSRID(ST_Point(yourLongitude, yourLatitude), 4326), ST_SRID(rast)) FROM yourTable WHERE ST_Intersects(rast, ST_Transform(ST_SetSRID(ST_Point(yourLongitude, yourLatitude), 4326), ST_SRID(rast))) In this case all points outside the area covered by the raster will not be returned. Pierre _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
