I have lots of (multi)polygons generated with this tool: http://gis.ucla.edu/apps/click2shp/
It provides a zip with dbf, shp, shx, prj files. The prj file contains the following:
GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
Which is EPSG:4326 as I understand.
Polygons are loaded to the Postgres + PostGIS database using some third party library (unknown to me). And it is accessible as WKB or WKT using SQL.
The polygons are spread all over the world - USA, Australia, Europe, potentially anywhere.
What I need is the projected coordinate system for each of these polygons to calculate their areas.
So far I've tried exploring
http://www.epsg-registry.org
that allows me to identify the CRS using some point or bounding box.
But maybe there's a better (preferably automated) solution.
ST_Area(geomcol::geography)