ST_GeogFromText — Return a specified geography value from Well-Known Text representation or extended (WKT).
geography ST_GeogFromText(text EWKT
Returns a geography object from the well-known text or extended well-known representation. SRID 4326 is assumed. This is an alias for ST_GeographyFromText. Points are always expressed in long lat form.
--- converting lon lat coords to geography ALTER TABLE sometable ADD COLUMN geog geography(POINT,4326); UPDATE sometable SET geog = ST_GeogFromText('SRID=4326;POINT(' || lon || ' ' || lat || ')');