def geom_area_diffs(**kwargs):
""" Calculates the spatial difference between the first and the last
version of the same area. Function requires at least two areas. """
list_current = current_data(**kwargs)
for current in list_current:
if current.geom_type == 'multipolygons':
features = session.query(Feature).filter(
Feature.osm_id == current.osm_id).order_by(
Feature.osm_version).all()
if len(features) < 2:
result = str(0.0)
else:
area1 = session.query(func.ST_Area(func.ST_GeogFromText(
func.ST_AsText(GeomMultiPolygon.the_geom)))).filter(
GeomMultiPolygon.feature_id == features[0].id).first()[0]
area2 = session.query(func.ST_Area(func.ST_GeogFromText(
func.ST_AsText(GeomMultiPolygon.the_geom)))).filter(
GeomMultiPolygon.feature_id == features[1].id).first()[0]
result = str(area2 - area1)
save_result(kwargs['job_op_id'], current.osm_id, result)
def geom_sum_dist(**kwargs):
""" Calculates the cumulative distance accross points.
Function requires at least three points. """
list_current = current_data(**kwargs)
for current in list_current:
if current.geom_type == 'points':
features = session.query(Feature).filter(
Feature.osm_id == current.osm_id).order_by(
Feature.osm_version).all()
result = 0.0
if len(features) >= 3:
for i, feature in enumerate(features):
if i != 0:
geog1 = session.query(func.ST_GeogFromText(
func.ST_AsText(GeomPoint.the_geom))).filter(
GeomPoint.feature_id == features[i - 1].id).first()[0]
geog2 = session.query(func.ST_GeogFromText(
func.ST_AsText(GeomPoint.the_geom))).filter(
GeomPoint.feature_id == feature.id).first()[0]
result += session.query(func.ST_Distance(
geog1, geog2, True)).first()[0]
save_result(kwargs['job_op_id'], current.osm_id, result)
def geom_from_original(**kwargs):
""" Calculates the distance from the first point.
Function requires at least two points. """
list_current = current_data(**kwargs)
for current in list_current:
if current.geom_type == 'points':
features = session.query(Feature).filter(
Feature.osm_id == current.osm_id).order_by(
Feature.osm_version).all()
if len(features) < 2:
result = '0'
else:
geog1 = session.query(func.ST_GeogFromText(func.ST_AsText(
GeomPoint.the_geom))).filter(
GeomPoint.feature_id == features[0].id).first()[0]
geog2 = session.query(func.ST_GeogFromText(func.ST_AsText(
GeomPoint.the_geom))).filter(
GeomPoint.feature_id == features[-1].id).first()[0]
result = session.query(
func.ST_Distance(geog1, geog2, True)).first()[0]
save_result(kwargs['job_op_id'], current.osm_id, str(result))
def geom_length_diffs(**kwargs):
""" Calculates the spatial difference between the first and the last
version of the same line. Function requires at least two lines. """
list_current = current_data(**kwargs)
for current in list_current:
if (current.geom_type == 'lines'
or current.geom_type == 'multilinestrings'):
features = session.query(Feature).filter(
Feature.osm_id == current.osm_id).order_by(
Feature.osm_version).all()
if len(features) < 2:
result = str(0.0)
else:
if current.geom_type == 'lines':
length1 = session.query(func.ST_Length(func.ST_GeogFromText(
func.ST_AsText(GeomLine.the_geom)))).filter(
GeomLine.feature_id == features[0].id).first()[0]
length2 = session.query(func.ST_Length(func.ST_GeogFromText(
func.ST_AsText(GeomLine.the_geom)))).filter(
GeomLine.feature_id == features[1].id).first()[0]
else:
length1 = session.query(func.ST_Length(func.ST_GeogFromText(
func.ST_AsText(GeomMultiLine.the_geom)))).filter(
GeomMultiLine.feature_id == features[0].id).first()[0]
length2 = session.query(func.ST_Length(func.ST_GeogFromText(
func.ST_AsText(GeomMultiLine.the_geom)))).filter(
GeomMultiLine.feature_id == features[1].id).first()[0]
result = str(length2 - length1)
save_result(kwargs['job_op_id'], current.osm_id, result)
