We are saving our drawn polygons in our database with the coordinate system 4326. The polygons drawn are all in Spain (where I came to find out the adequate coordinate system for Spain is EPSG:2062).
This been said, which one will calculate with more accuracy the area of the polygon?
"st_area(polygon)" or "ST_area(ST_Transform(polygon::geometry, 2062))"?
I know that using the one related to my country will give me (in theory) the most accurate results/georeferencing, but is it really true? Also, and since we are drawing in a map that only supports 4326, will we have a more accurate calculated area by converting the coordinate system and calculating afterwards, or should we calculate the area with the current coordinate system?
ST_Area()
call won't work unless the polygon is ingeography
. Have you tried a systematic comparison in four or five valid projections, to determine the difference, then chosen a selection of features for further evaluation? Without detailed information of the geometries involved (including numbers of vertices and precision and accuracy of the sources), there's no way to make a determination of which is more accurate.geometry
the result is square Cartesian degrees, which is useless. The inaccuracies introduced by either geodesic or projected area calculation are three to five orders of magnitude less significant than your vertex collection precision.