def test_Grid(self):
from utils.grid import latlon_to_grid, grid_to_latlon
lats = [ 33.995833, -5.6625, -3.1375, 6.12083]
lons = [-112.004167, 106.104167, -12.412541, 85.22916]
for lat, lon in map(None, lats, lons):
grid = latlon_to_grid(lat, lon)
lat2, lon2 = grid_to_latlon(grid)
self.assertAlmostEqual(lat, lat2, places=4)
self.assertAlmostEqual(lon, lon2, places=4)
def _outputGeometryFromGridId(self, grid_id):
[lat, lon] = grid_to_latlon(int(grid_id))
return QgsGeometry.fromRect(
QgsRectangle(
lon - DEFAULT_HALF_GRID_SIZE,
lat - DEFAULT_HALF_GRID_SIZE,
lon + DEFAULT_HALF_GRID_SIZE,
lat + DEFAULT_HALF_GRID_SIZE,
)
)
def _outputGeometryFromGridId(self, grid_id):
[lat, lon] = grid_to_latlon(int(grid_id))
return QgsGeometry.fromRect(QgsRectangle(lon-DEFAULT_HALF_GRID_SIZE, lat-DEFAULT_HALF_GRID_SIZE,
lon+DEFAULT_HALF_GRID_SIZE, lat+DEFAULT_HALF_GRID_SIZE))
@logAPICall
def do_operation(self):
""" perform create mapping scheme operation """
# input/output verification already performed during set input/ouput
svy_layer = self.inputs[0].value
# make sure input is correct
# NOTE: these checks cannot be performed at set input time
# because the data layer maybe is not loaded yet
self._test_layer_loaded(svy_layer)
total_features = svy_layer.dataProvider().featureCount()
if total_features > MAX_FEATURES_IN_MEMORY:
# use bsddb to store temporary lat/lon
tmp_db_file = '%sdb_%s.db' % (self._tmp_dir, get_unique_filename())
db = bsddb.btopen(tmp_db_file, 'c')
else:
db = {}
# tally statistics for each grid_id/building type combination
tax_idx = layer_field_index(svy_layer, TAX_FIELD_NAME)
for f in layer_features(svy_layer):
geom = f.geometry()
centroid = geom.centroid().asPoint()
grid_id = latlon_to_grid(centroid.y(), centroid.x())
tax_str = str(f.attributeMap()[tax_idx].toString())
key = '%s %s' % (tax_str, grid_id)
if db.has_key(key):
db[key] = str(int(db[key]) + 1) # value as string required by bsddb
else:
db[key] = '1' # value as string required by bsddb
# loop through all zones and assign mapping scheme
# outputs
exposure_layername = 'exp_%s' % get_unique_filename()
exposure_file = '%s%s.shp' % (self._tmp_dir, exposure_layername)
try:
writer = QgsVectorFileWriter(exposure_file, "utf-8",
self._fields, self._outputGeometryType(), self._crs,
"ESRI Shapefile")
f = QgsFeature()
gid = 0
for key, val in db.iteritems():
(tax_str, grid_id) = key.split(' ')
lon, lat = grid_to_latlon(int(grid_id))
f.setGeometry(self._outputGeometryFromGridId(grid_id))
f.addAttribute(0, QVariant(grid_id))
f.addAttribute(1, QVariant(lon))
f.addAttribute(2, QVariant(lat))
f.addAttribute(3, QVariant(tax_str))
f.addAttribute(4, QVariant(''))
f.addAttribute(5, QVariant(val))
writer.addFeature(f)
gid += 1
del writer, f
except Exception as err:
remove_shapefile(exposure_file)
raise OperatorError("error creating exposure file: %s" % err, self.__class__)
# load shapefile as layer
exposure_layer = load_shapefile(exposure_file, exposure_layername)
if not exposure_layer:
raise OperatorError('Error loading exposure file %s' % (exposure_file), self.__class__)
# store data in output
self.outputs[0].value = exposure_layer
def do_operation(self):
""" perform create mapping scheme operation """
# input/output verification already performed during set input/ouput
svy_layer = self.inputs[0].value
# make sure input is correct
# NOTE: these checks cannot be performed at set input time
# because the data layer maybe is not loaded yet
self._test_layer_loaded(svy_layer)
total_features = svy_layer.dataProvider().featureCount()
if total_features > MAX_FEATURES_IN_MEMORY:
# use bsddb to store temporary lat/lon
tmp_db_file = '%sdb_%s.db' % (self._tmp_dir, get_unique_filename())
db = bsddb.btopen(tmp_db_file, 'c')
else:
db = {}
# tally statistics for each grid_id/building type combination
tax_idx = layer_field_index(svy_layer, TAX_FIELD_NAME)
for f in layer_features(svy_layer):
geom = f.geometry()
centroid = geom.centroid().asPoint()
grid_id = latlon_to_grid(centroid.y(), centroid.x())
tax_str = str(f.attributeMap()[tax_idx].toString())
key = '%s %s' % (tax_str, grid_id)
if db.has_key(key):
db[key] = str(int(db[key]) +
1) # value as string required by bsddb
else:
db[key] = '1' # value as string required by bsddb
# loop through all zones and assign mapping scheme
# outputs
exposure_layername = 'exp_%s' % get_unique_filename()
exposure_file = '%s%s.shp' % (self._tmp_dir, exposure_layername)
try:
writer = QgsVectorFileWriter(exposure_file, "utf-8", self._fields,
self._outputGeometryType(), self._crs,
"ESRI Shapefile")
f = QgsFeature()
gid = 0
for key, val in db.iteritems():
(tax_str, grid_id) = key.split(' ')
lon, lat = grid_to_latlon(int(grid_id))
f.setGeometry(self._outputGeometryFromGridId(grid_id))
f.addAttribute(0, QVariant(grid_id))
f.addAttribute(1, QVariant(lon))
f.addAttribute(2, QVariant(lat))
f.addAttribute(3, QVariant(tax_str))
f.addAttribute(4, QVariant(''))
f.addAttribute(5, QVariant(val))
writer.addFeature(f)
gid += 1
del writer, f
except Exception as err:
remove_shapefile(exposure_file)
raise OperatorError("error creating exposure file: %s" % err,
self.__class__)
# load shapefile as layer
exposure_layer = load_shapefile(exposure_file, exposure_layername)
if not exposure_layer:
raise OperatorError(
'Error loading exposure file %s' % (exposure_file),
self.__class__)
# store data in output
self.outputs[0].value = exposure_layer
self.outputs[1].value = exposure_file
