def create_grid(size):
"""Create a polygonal grid using Processing.
:param size: The cell size.
:type size: int
:return: The grid layer in memory.
:rtype: QgsVectorLayer
"""
output_filename = unique_filename(prefix='grid', suffix='.shp')
result = processing.runalg(
'qgis:vectorgrid',
'336199.970553,352338.397991,7636164.67975,7648562.41208',
size, # X spacing
size, # Y spacing
0, # Output as polygons
output_filename)
layer = QgsVectorLayer(output_filename, 'grid', 'ogr')
layer.setCrs(QgsCoordinateReferenceSystem(32740))
remove_fields(layer, ['xmin', 'xmax', 'ymin', 'ymax'])
# Make a copy in memory
memory = create_memory_layer(
'grid', layer.geometryType(), layer.crs(), layer.fields())
copy_layer(layer, memory)
print "NB cells : %s" % layer.featureCount()
return memory
def create_grid(size):
"""Create a polygonal grid using Processing.
:param size: The cell size.
:type size: int
:return: The grid layer in memory.
:rtype: QgsVectorLayer
"""
output_filename = unique_filename(prefix='grid', suffix='.shp')
result = processing.runalg(
'qgis:vectorgrid',
'336199.970553,352338.397991,7636164.67975,7648562.41208',
size, # X spacing
size, # Y spacing
0, # Output as polygons
output_filename)
layer = QgsVectorLayer(output_filename, 'grid', 'ogr')
layer.setCrs(QgsCoordinateReferenceSystem(32740))
remove_fields(layer, ['xmin', 'xmax', 'ymin', 'ymax'])
# Make a copy in memory
memory = create_memory_layer(
'grid', layer.geometryType(), layer.crs(), layer.fields())
copy_layer(layer, memory)
def reproject(layer, output_crs):
"""Reproject a vector layer to a specific CRS.
Issue https://github.com/inasafe/inasafe/issues/3183
:param layer: The layer to reproject.
:type layer: QgsVectorLayer
:param output_crs: The destination CRS.
:type output_crs: QgsCoordinateReferenceSystem
:return: Reprojected memory layer.
:rtype: QgsVectorLayer
"""
input_crs = layer.crs()
input_fields = layer.fields()
reprojected = create_memory_layer(
'reprojected', layer.geometryType(), output_crs, input_fields)
reprojected.startEditing()
crs_transform = QgsCoordinateTransform(input_crs, output_crs)
out_feature = QgsFeature()
for feature in layer.getFeatures():
geom = feature.geometry()
geom.transform(crs_transform)
out_feature.setGeometry(geom)
out_feature.setAttributes(feature.attributes())
reprojected.addFeature(out_feature)
reprojected.commitChanges()
return reprojected
def reproject(layer, output_crs):
"""Reproject a vector layer to a specific CRS.
Issue https://github.com/inasafe/inasafe/issues/3183
:param layer: The layer to reproject.
:type layer: QgsVectorLayer
:param output_crs: The destination CRS.
:type output_crs: QgsCoordinateReferenceSystem
:return: Reprojected memory layer.
:rtype: QgsVectorLayer
"""
input_crs = layer.crs()
input_fields = layer.fields()
reprojected = create_memory_layer('reprojected', layer.geometryType(),
output_crs, input_fields)
reprojected.startEditing()
crs_transform = QgsCoordinateTransform(input_crs, output_crs)
out_feature = QgsFeature()
for feature in layer.getFeatures():
geom = feature.geometry()
geom.transform(crs_transform)
out_feature.setGeometry(geom)
out_feature.setAttributes(feature.attributes())
reprojected.addFeature(out_feature)
reprojected.commitChanges()
return reprojected
def centroids(layer):
"""Create centroids."""
centroids_layer = create_memory_layer(
'centroids',
Qgis.Point,
layer.crs(),
layer.fields())
centroids_layer.startEditing()
for feature in layer.getFeatures():
new_feature = QgsFeature(feature)
new_feature.setGeometry(feature.geometry().centroid())
centroids_layer.addFeature(new_feature)
centroids_layer.commitChanges()
return centroids_layer
def centroids(layer):
"""Create centroids."""
centroids_layer = create_memory_layer(
'centroids',
QGis.Point,
layer.crs(),
layer.fields())
centroids_layer.startEditing()
for feature in layer.getFeatures():
new_feature = QgsFeature(feature)
new_feature.setGeometry(feature.geometry().centroid())
centroids_layer.addFeature(new_feature)
centroids_layer.commitChanges()
return centroids_layer
def show_qgis_feature(feature, crs=None):
"""Show a QGIS feature.
:param feature: The feature to display.
:type feature: QgsFeature
:param crs: The CRS of the geometry. 4326 by default.
:type crs: QgsCoordinateReferenceSystem
"""
if crs is None:
crs = QgsCoordinateReferenceSystem(4326)
layer = create_memory_layer('Debug', feature.geometry().type(), crs)
data_provider = layer.dataProvider()
for i, attr in enumerate(feature.attributes()):
data_provider.addAttributes(
[QgsField('attribute %s' % i, QVariant.String)])
layer.updateFields()
data_provider.addFeatures([feature])
layer.updateExtents()
show_qgis_layer(layer)
def assign_cost_to_cells(network_graph, source, destination, id_field):
"""Assign the nearest destination point from the source layer.
:param network_graph: The network graph.
:type network_graph: Graph
:param source: Grid as a polygon vector layer
:type source: QgsVectorLayer
:param destination: The destination point layer.
:type destination: QgsVectorLayer
:param id_field: The ID field in the destination layer.
:type id_field: basestring
"""
spatial_index = create_spatial_index(destination)
destination_features = {}
for feature in destination.getFeatures():
destination_features[feature.id()] = feature
index_id_field = destination.fields().indexFromName(id_field)
fields = [QgsField('distance', QVariant.Int)]
routes = create_memory_layer(
'routes', Qgis.Line, destination.crs(), fields)
routes.startEditing()
source.startEditing()
source.addAttribute(
QgsField('destination_id', QVariant.Int, len=5, prec=0))
dest_id_field = source.fields().indexFromName('destination_id')
source.addAttribute(QgsField('distance', QVariant.Int, len=5, prec=0))
distance_field = source.fields().indexFromName('distance')
source.commitChanges()
request = QgsFeatureRequest()
request.setFilterExpression('"has_road" = \'true\'')
# request.setLimit(20) # Hack for now to speedup development
i = 0
for source_cell in source.getFeatures(request):
source_geometry_point = source_cell.geometry().centroid().asPoint()
desination_id = source_cell['destination_id']
if desination_id is None or isinstance(desination_id, QPyNullVariant):
source.startEditing()
nearest_health_points = spatial_index.nearestNeighbor(
source_geometry_point, 5)
minimum_distance = None
minimal_geom = None
for health_point in nearest_health_points:
try:
i += 1
p = destination_features[health_point].geometry().asPoint()
geom, distance, _ = network_graph.route(
source_geometry_point, p)
except:
distance = -1
if minimum_distance is None or (
minimum_distance > distance >= 0):
minimal_geom = geom
minimum_distance = distance
if minimum_distance:
feature = QgsFeature()
feature.setGeometry(minimal_geom)
feature.setAttributes([minimum_distance])
routes.addFeatures([feature])
index_id = destination_features[health_point][index_id_field]
destination_value = index_id
else:
destination_value = '-1'
minimum_distance = '-1'
source.changeAttributeValue(
source_cell.id(), dest_id_field, destination_value)
source.changeAttributeValue(
source_cell.id(), distance_field, minimum_distance)
intersecting_blocks(minimal_geom, destination_value, grid)
source.commitChanges()
else:
# fix_print_with_import
print('speedup')
geom, distance, _ = network_graph.route(
source_geometry_point,
destination_features[desination_id].geometry().asPoint())
source.commitChanges()
# source.commitErrors()
routes.commitChanges()
def assign_cost_to_cells(network_graph, source, destination, id_field):
"""Assign the nearest destination point from the source layer.
:param network_graph: The network graph.
:type network_graph: Graph
:param source: Grid as a polygon vector layer
:type source: QgsVectorLayer
:param destination: The destination point layer.
:type destination: QgsVectorLayer
:param id_field: The ID field in the destination layer.
:type id_field: basestring
"""
spatial_index = create_spatial_index(destination)
destination_features = {}
for feature in destination.getFeatures():
destination_features[feature.id()] = feature
index_id_field = destination.fieldNameIndex(id_field)
fields = [QgsField('distance', QVariant.Int)]
routes = create_memory_layer(
'routes', QGis.Line, destination.crs(), fields)
routes.startEditing()
source.startEditing()
source.addAttribute(
QgsField('destination_id', QVariant.Int, len=5, prec=0))
dest_id_field = source.fieldNameIndex('destination_id')
source.addAttribute(QgsField('distance', QVariant.Int, len=5, prec=0))
distance_field = source.fieldNameIndex('distance')
source.commitChanges()
request = QgsFeatureRequest()
request.setFilterExpression('"has_road" = \'true\'')
# request.setLimit(20) # Hack for now to speedup development
i = 0
for source_cell in source.getFeatures(request):
source_geometry_point = source_cell.geometry().centroid().asPoint()
desination_id = source_cell['destination_id']
if desination_id is None or isinstance(desination_id, QPyNullVariant):
source.startEditing()
nearest_health_points = spatial_index.nearestNeighbor(
source_geometry_point, 5)
minimum_distance = None
minimal_geom = None
for health_point in nearest_health_points:
try:
i += 1
p = destination_features[health_point].geometry().asPoint()
geom, distance, _ = network_graph.route(
source_geometry_point, p)
except:
distance = -1
if minimum_distance is None or (
minimum_distance > distance >= 0):
minimal_geom = geom
minimum_distance = distance
if minimum_distance:
feature = QgsFeature()
feature.setGeometry(minimal_geom)
feature.setAttributes([minimum_distance])
routes.addFeatures([feature])
index_id = destination_features[health_point][index_id_field]
destination_value = index_id
else:
destination_value = '-1'
minimum_distance = '-1'
source.changeAttributeValue(
source_cell.id(), dest_id_field, destination_value)
source.changeAttributeValue(
source_cell.id(), distance_field, minimum_distance)
intersecting_blocks(minimal_geom, destination_value, grid)
source.commitChanges()
else:
print 'speedup'
geom, distance, _ = network_graph.route(
source_geometry_point,
destination_features[desination_id].geometry().asPoint())
source.commitChanges()
# source.commitErrors()
routes.commitChanges()
print 'Call : %s' % i
return routes, source