seattlecitylight-mastodon-bot/geospatial.py

30 lines
924 B
Python

from shapely import MultiPolygon, Polygon, Geometry, to_wkb, from_wkb
from sqlalchemy.types import TypeDecorator, LargeBinary
def convert_outage_geometry(event) -> MultiPolygon:
assert event["polygons"]["type"] == "polygon"
assert event["polygons"]["hasZ"] is False
assert event["polygons"]["hasM"] is False
polygon_list = []
for ring in event["polygons"]["rings"]:
polygon_list.append(Polygon(ring))
return MultiPolygon(polygon_list)
class DBGeometry(TypeDecorator):
impl = LargeBinary
cache_ok = True
def process_bind_param(self, value, dialect):
if isinstance(value, Geometry):
value = to_wkb(value)
return value
def process_result_value(self, value, dialect):
if value is None:
return value
else:
if not isinstance(value, Geometry):
value = from_wkb(value)
return value