Geometry point - postgis

// add geom column

cmd.CommandText = "alter table m7_data_table add column geom geometry(point,4326)";

 cmd.ExecuteNonQuery();

// update geom column -- combine lon and lat

cmd.CommandText = "UPDATE m7_data_table SET geom = ST_SetSRID(ST_Makepoint(Lat,Lon),4326) where geom isnull";

cmd.ExecuteNonQuery();

** to use geometry:

> CREATE EXTENSION IF NOT EXISTS postgis;";