geoalchemy Geometry wrapper for simple "lat,lon" fields

gistfile1.py

from sqlalchemy import types
from sqlalchemy.sql.expression import func, text
from geoalchemy2 import functions as geofunc
from geoalchemy2.elements import WKTElement


class Coordinate(types.TypeDecorator):
    impl = Geometry

    def process_bind_param(self, value, dialect):
        return 'POINT({} {})'.format(*value.split(',', 1))

    def bind_expression(self, bindvalue):
        return func.ST_GeomFromText(bindvalue, self.srid, type_=self)

    def column_expression(self, bindvalue):
        return geofunc.ST_Y(bindvalue, type_=types.String) + text("','") + geofunc.ST_X(bindvalue, type_=types.String)