def make_grid(self, resolution, geom=None, conditions=None):
"""
:param resolution: length of side of grid square in meters
:type resolution: int
:param geom: string representation of geojson fragment
:type geom: str
:param conditions: conditions on columns to filter on
:type conditions: list of SQLAlchemy binary operations
(e.g. col > value)
:return: grid: result proxy with all result rows
size_x, size_y: the horizontal and vertical size
of the grid squares in degrees
"""
if conditions is None:
conditions = []
# We need to convert resolution (given in meters) to degrees
# - which is the unit of measure for EPSG 4326 -
# - in order to generate our grid.
center = self.get_bbox_center()
# center[1] is longitude
size_x, size_y = get_size_in_degrees(resolution, center[1])
# Generate a count for each resolution by resolution square
t = self.point_table
q = session.query(func.count(t.c.hash),
func.ST_SnapToGrid(t.c.geom, size_x, size_y)
.label('squares'))\
.filter(*conditions)\
.group_by('squares')
if geom:
q = q.filter(t.c.geom.ST_Within(func.ST_GeomFromGeoJSON(geom)))
return session.execute(q), size_x, size_y
def make_grid(self, resolution, geom=None, conditions=None):
"""
:param resolution: length of side of grid square in meters
:type resolution: int
:param geom: string representation of geojson fragment
:type geom: str
:param conditions: conditions on columns to filter on
:type conditions: list of SQLAlchemy binary operations
(e.g. col > value)
:return: grid: result proxy with all result rows
size_x, size_y: the horizontal and vertical size
of the grid squares in degrees
"""
if conditions is None:
conditions = []
# We need to convert resolution (given in meters) to degrees
# - which is the unit of measure for EPSG 4326 -
# - in order to generate our grid.
center = self.get_bbox_center()
# center[1] is longitude
size_x, size_y = get_size_in_degrees(resolution, center[1])
# Generate a count for each resolution by resolution square
t = self.point_table
q = session.query(func.count(t.c.hash),
func.ST_SnapToGrid(t.c.geom, size_x, size_y)
.label('squares'))\
.filter(*conditions)\
.group_by('squares')
if geom:
q = q.filter(t.c.geom.ST_Within(func.ST_GeomFromGeoJSON(geom)))
return session.execute(q), size_x, size_y
def make_fragment_str(geojson_fragment, buffer=100):
if geojson_fragment['type'] == 'LineString':
shape = asShape(geojson_fragment)
lat = shape.centroid.y
x, y = get_size_in_degrees(buffer, lat)
geojson_fragment = shape.buffer(y).__geo_interface__
geojson_fragment['crs'] = {"type": "name", "properties": {"name": "EPSG:4326"}}
return json.dumps(geojson_fragment)
def make_fragment_str(geojson_fragment, buffer=100):
if geojson_fragment['type'] == 'LineString':
shape = asShape(geojson_fragment)
lat = shape.centroid.y
x, y = get_size_in_degrees(buffer, lat)
geojson_fragment = shape.buffer(y).__geo_interface__
geojson_fragment['crs'] = {"type": "name", "properties": {"name": "EPSG:4326"}}
return json.dumps(geojson_fragment)
def make_query(table, raw_query_params):
table_keys = table.columns.keys()
args_keys = raw_query_params.keys()
resp = {
'meta': {
'status': 'error',
'message': '',
},
'objects': [],
}
status_code = 200
query_clauses = []
valid_query = True
#print "make_query(): args_keys = ", args_keys
if 'offset' in args_keys:
args_keys.remove('offset')
if 'limit' in args_keys:
args_keys.remove('limit')
if 'order_by' in args_keys:
args_keys.remove('order_by')
if 'weather' in args_keys:
args_keys.remove('weather')
for query_param in args_keys:
try:
field, operator = query_param.split('__')
#print "make_query(): field, operator =", field, operator
except ValueError:
field = query_param
operator = 'eq'
query_value = raw_query_params.get(query_param)
column = table.columns.get(field)
if field not in table_keys:
resp['meta']['message'] = '"%s" is not a valid fieldname' % field
status_code = 400
valid_query = False
elif operator == 'in':
query = column.in_(query_value.split(','))
query_clauses.append(query)
elif operator == 'within':
geo = json.loads(query_value)
#print "make_query(): geo is", geo.items()
if 'features' in geo.keys():
val = geo['features'][0]['geometry']
elif 'geometry' in geo.keys():
val = geo['geometry']
else:
val = geo
if val['type'] == 'LineString':
shape = shapely.geometry.asShape(val)
lat = shape.centroid.y
# 100 meters by default
x, y = get_size_in_degrees(100, lat)
val = shape.buffer(y).__geo_interface__
val['crs'] = {"type": "name", "properties": {"name": "EPSG:4326"}}
query = column.ST_Within(func.ST_GeomFromGeoJSON(json.dumps(val)))
#print "make_query: val=", val
#print "make_query(): query = ", query
query_clauses.append(query)
elif operator.startswith('time_of_day'):
if operator.endswith('ge'):
query = func.date_part('hour', column).__ge__(query_value)
elif operator.endswith('le'):
query = func.date_part('hour', column).__le__(query_value)
query_clauses.append(query)
else:
try:
attr = filter(lambda e: hasattr(column, e % operator),
['%s', '%s_', '__%s__'])[0] % operator
except IndexError:
resp['meta'][
'message'] = '"%s" is not a valid query operator' % operator
status_code = 400
valid_query = False
break
if query_value == 'null': # pragma: no cover
query_value = None
query = getattr(column, attr)(query_value)
query_clauses.append(query)
#print "make_query(): query_clauses=", query_clauses
return valid_query, query_clauses, resp, status_code
def make_query(table, raw_query_params):
table_keys = table.columns.keys()
args_keys = raw_query_params.keys()
resp = {
'meta': {
'status': 'error',
'message': '',
},
'objects': [],
}
status_code = 200
query_clauses = []
valid_query = True
#print "make_query(): args_keys = ", args_keys
if 'offset' in args_keys:
args_keys.remove('offset')
if 'limit' in args_keys:
args_keys.remove('limit')
if 'order_by' in args_keys:
args_keys.remove('order_by')
if 'weather' in args_keys:
args_keys.remove('weather')
for query_param in args_keys:
try:
field, operator = query_param.split('__')
#print "make_query(): field, operator =", field, operator
except ValueError:
field = query_param
operator = 'eq'
query_value = raw_query_params.get(query_param)
column = table.columns.get(field)
if field not in table_keys:
resp['meta']['message'] = '"%s" is not a valid fieldname' % field
status_code = 400
valid_query = False
elif operator == 'in':
query = column.in_(query_value.split(','))
query_clauses.append(query)
elif operator == 'within':
geo = json.loads(query_value)
#print "make_query(): geo is", geo.items()
if 'features' in geo.keys():
val = geo['features'][0]['geometry']
elif 'geometry' in geo.keys():
val = geo['geometry']
else:
val = geo
if val['type'] == 'LineString':
shape = shapely.geometry.asShape(val)
lat = shape.centroid.y
# 100 meters by default
x, y = get_size_in_degrees(100, lat)
val = shape.buffer(y).__geo_interface__
val['crs'] = {"type":"name","properties":{"name":"EPSG:4326"}}
query = column.ST_Within(func.ST_GeomFromGeoJSON(json.dumps(val)))
#print "make_query: val=", val
#print "make_query(): query = ", query
query_clauses.append(query)
elif operator.startswith('time_of_day'):
if operator.endswith('ge'):
query = func.date_part('hour', column).__ge__(query_value)
elif operator.endswith('le'):
query = func.date_part('hour', column).__le__(query_value)
query_clauses.append(query)
else:
try:
attr = filter(
lambda e: hasattr(column, e % operator),
['%s', '%s_', '__%s__']
)[0] % operator
except IndexError:
resp['meta']['message'] = '"%s" is not a valid query operator' % operator
status_code = 400
valid_query = False
break
if query_value == 'null': # pragma: no cover
query_value = None
query = getattr(column, attr)(query_value)
query_clauses.append(query)
#print "make_query(): query_clauses=", query_clauses
return valid_query, query_clauses, resp, status_code