sqlalchemy.func.ST_AsGeoJSON - python examples

Here are the examples of the python api sqlalchemy.func.ST_AsGeoJSON taken from open source projects. By voting up you can indicate which examples are most useful and appropriate.

1 Examples 7

0 View Complete Implementation : cli.py
Copyright GNU General Public License v3.0
Author : EdwardBetts
@app.cli.command()
@click.argument('place_identifier')
def polygons(place_identifier):
    place = get_place(place_identifier)

    chunk_size = utils.calc_chunk_size(place.area_in_sq_km)
    place_geojson = (database.session.query(func.ST_AsGeoJSON(Place.geom, 4))
                                     .filter(Place.place_id == place.place_id)
                                     .scalar())
    # print(place_geojson)
    for chunk in place.chunk_n(chunk_size):
        print(', '.join('{:.3f}'.format(i) for i in chunk))

        (ymin, ymax, xmin, xmax) = chunk

        clip = func.ST_Intersection(Place.geom,
                                    func.ST_MakeEnvelope(xmin, ymin, xmax, ymax))

        chunk_geojson = (database.session
                                 .query(func.ST_AsGeoJSON(clip, 4))
                                 .filter(Place.place_id == place.place_id)
                                 .scalar())

        print(chunk_geojson)