Compute the surface of WKT geometries in square meters. Stores the result in a novel column of type Double.
In order to compute the size of the area in square meters, the node reprojects on the fly the geometries into an automatic projection  as defined by the Open Geospatial Consortium . This might lead to conversion errors in case your initial Coordinate Reference System is not an ESPG standard one. If you get errors related to Bursa Wolf parameters or similar errors due to projection, please try to use the "Reproject WKT geometries" in order to first reproject your geometries into a welldefined CRS.
The actual computation is done by the powerful Geotools library.