def geom_from_text(well_known_text, srid=None):
"""
Define function call for converting well-known text representation to PostGIS geometry object.
:param well_known_text: well-known text representation of geometry (string)
:return: SQL function (sqlalchemy.sql.functions.Function)
"""
if (srid is None):
return func.ST_GeomFromText(well_known_text)
else:
return func.ST_GeomFromText(well_known_text, srid)
def match_point(self, s):
if isinstance(s, str):
try:
point = Point.from_string(s)
except ValueError:
return None
normalized_point = point
if self.is_lat_long(point):
point = point.reproject()
geom = func.ST_GeomFromText(point.wkt, DEFAULT_SRID)
distance = func.ST_Distance(geom, Intersection.geom)
distance = distance.label('distance')
# Try to get an Intersection first
q = self.session.query(Intersection, distance)
q = q.filter(distance < 5) # 5 meters (make configurable)
q = q.order_by(distance)
result = q.first()
if result is not None:
closest_object = result.Intersection
closest_point = closest_object.geom
else:
# Otherwise, get a Street
distance = func.ST_Distance(geom, Street.geom).label('distance')
q = self.session.query(Street, distance)
q = q.order_by(distance)
closest_object = q.first().Street
# Get point on Street closest to input point
closest_point = func.ST_ClosestPoint(Street.geom, geom)
closest_point = closest_point.label('closest_point')
q = self.session.query(closest_point).select_from(Street)
q = q.filter_by(id=closest_object.id)
closest_point = q.scalar()
closest_point = Point.from_wkb(closest_point)
name = closest_object.name
return LookupResult(s, normalized_point, closest_point, closest_object, name)
def match_point(self, s):
if isinstance(s, str):
try:
point = Point.from_string(s)
except ValueError:
return None
normalized_point = point
geom = func.ST_GeomFromText(point.wkt, DEFAULT_SRID)
distance = func.ST_Distance(
func.ST_GeogFromWKB(geom),
func.ST_GeogFromWKB(Intersection.geom))
distance = distance.label('distance')
# Distance threshold in meters
# TODO: Should this be scale-dependent?
distance_threshold = self.config.get('distance_threshold', 10)
# Try to get an Intersection first
q = self.session.query(Intersection, distance)
q = q.filter(distance < distance_threshold)
q = q.order_by(distance)
result = q.first()
if result is not None:
closest_object = result.Intersection
closest_point = closest_object.geom
name = closest_object.name
else:
# Otherwise, get a Street
distance = func.ST_Distance(geom, Street.geom).label('distance')
q = self.session.query(Street, distance)
q = q.filter(
Street.highway.in_(Street.routable_types) |
Street.bicycle.in_(Street.bicycle_allowed_types)
)
q = q.order_by(distance)
closest_object = q.first().Street
# Get point on Street closest to input point
closest_point = func.ST_ClosestPoint(Street.geom, geom)
closest_point = closest_point.label('closest_point')
q = self.session.query(closest_point).select_from(Street)
q = q.filter_by(id=closest_object.id)
closest_point = q.scalar()
closest_point = Point.from_wkb(closest_point)
name = closest_object.display_name
return LookupResult(s, normalized_point, closest_point, closest_object, name, 'byCycle point')
def ST_GeoFromText(self, x):
return func.ST_GeomFromText(x, 4326)