def testSubsetAttributes(self):
req = QgsFeatureRequest()
self.assertFalse(req.subsetOfAttributes())
self.assertFalse(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
req.setSubsetOfAttributes([1, 4])
self.assertEqual(req.subsetOfAttributes(), [1, 4])
self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
req.setNoAttributes()
self.assertEqual(req.subsetOfAttributes(), [])
self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
req.setSubsetOfAttributes([])
self.assertFalse(req.subsetOfAttributes())
self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
req.setFlags(QgsFeatureRequest.Flags())
f = QgsFields()
f.append(QgsField('a', QVariant.String))
f.append(QgsField('b', QVariant.String))
f.append(QgsField('c', QVariant.String))
req.setSubsetOfAttributes(['a', 'c'], f)
self.assertEqual(req.subsetOfAttributes(), [0, 2])
self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
def testAssignment(self):
req = QgsFeatureRequest().setFilterFids([8, 9]).setFilterRect(
QgsRectangle(1, 2, 3, 4)).setInvalidGeometryCheck(
QgsFeatureRequest.GeometrySkipInvalid).setLimit(6).setFlags(
QgsFeatureRequest.ExactIntersect).setSubsetOfAttributes(
[1, 4]).setTimeout(6).setRequestMayBeNested(True)
context = QgsExpressionContext()
scope = QgsExpressionContextScope()
scope.setVariable('a', 6)
context.appendScope(scope)
req.setExpressionContext(context)
method = QgsSimplifyMethod()
method.setMethodType(QgsSimplifyMethod.PreserveTopology)
req.setSimplifyMethod(method)
context = QgsCoordinateTransformContext()
req.setDestinationCrs(QgsCoordinateReferenceSystem('EPSG:3857'),
context)
req2 = QgsFeatureRequest(req)
self.assertEqual(req2.limit(), 6)
self.assertCountEqual(req2.filterFids(), [8, 9])
self.assertEqual(req2.filterRect(), QgsRectangle(1, 2, 3, 4))
self.assertEqual(req2.spatialFilterType(),
Qgis.SpatialFilterType.BoundingBox)
self.assertEqual(req2.invalidGeometryCheck(),
QgsFeatureRequest.GeometrySkipInvalid)
self.assertEqual(req2.expressionContext().scopeCount(), 1)
self.assertEqual(req2.expressionContext().variable('a'), 6)
self.assertEqual(
req2.flags(), QgsFeatureRequest.ExactIntersect
| QgsFeatureRequest.SubsetOfAttributes)
self.assertEqual(req2.subsetOfAttributes(), [1, 4])
self.assertEqual(req2.simplifyMethod().methodType(),
QgsSimplifyMethod.PreserveTopology)
self.assertEqual(req2.destinationCrs().authid(), 'EPSG:3857')
self.assertEqual(req2.timeout(), 6)
self.assertTrue(req2.requestMayBeNested())
# copy distance within request
req = QgsFeatureRequest().setDistanceWithin(
QgsGeometry.fromWkt('LineString( 0 0, 10 0, 11 2)'), 1.2)
req2 = QgsFeatureRequest(req)
self.assertEqual(req2.spatialFilterType(),
Qgis.SpatialFilterType.DistanceWithin)
self.assertEqual(req2.referenceGeometry().asWkt(),
'LineString (0 0, 10 0, 11 2)')
self.assertEqual(req2.distanceWithin(), 1.2)
self.assertEqual(req2.filterRect(),
QgsRectangle(-1.2, -1.2, 12.2, 3.2))
def processAlgorithm(self, parameters, context, feedback):
network = self.parameterAsSource(parameters, self.INPUT, context)
startPoints = self.parameterAsSource(parameters, self.START_POINTS, context)
endPoint = self.parameterAsPoint(parameters, self.END_POINT, context, network.sourceCrs())
strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
directionFieldName = self.parameterAsString(parameters, self.DIRECTION_FIELD, context)
forwardValue = self.parameterAsString(parameters, self.VALUE_FORWARD, context)
backwardValue = self.parameterAsString(parameters, self.VALUE_BACKWARD, context)
bothValue = self.parameterAsString(parameters, self.VALUE_BOTH, context)
defaultDirection = self.parameterAsEnum(parameters, self.DEFAULT_DIRECTION, context)
speedFieldName = self.parameterAsString(parameters, self.SPEED_FIELD, context)
defaultSpeed = self.parameterAsDouble(parameters, self.DEFAULT_SPEED, context)
tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
fields = QgsFields()
fields.append(QgsField('start', QVariant.String, '', 254, 0))
fields.append(QgsField('end', QVariant.String, '', 254, 0))
fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
feat = QgsFeature()
feat.setFields(fields)
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.LineString, network.sourceCrs())
directionField = -1
if directionFieldName:
directionField = network.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName:
speedField = network.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(network,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = context.project().crs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField,
defaultSpeed,
multiplier * 1000.0 / 3600.0)
multiplier = 3600
director.addStrategy(strategy)
builder = QgsGraphBuilder(network.sourceCrs(),
True,
tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
request.setDestinationCrs(network.sourceCrs())
features = startPoints.getFeatures(request)
total = 100.0 / startPoints.featureCount() if startPoints.featureCount() else 0
points = [endPoint]
for current, f in enumerate(features):
if feedback.isCanceled():
break
points.append(f.geometry().asPoint())
feedback.setProgress(int(current * total))
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points, feedback)
feedback.pushInfo(self.tr('Calculating shortest paths...'))
graph = builder.graph()
idxEnd = graph.findVertex(snappedPoints[0])
route = []
nPoints = len(snappedPoints)
total = 100.0 / nPoints if nPoints else 1
for i in range(1, nPoints + 1):
if feedback.isCanceled():
break
idxStart = graph.findVertex(snappedPoints[i])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
if tree[idxEnd] == -1:
msg = self.tr('There is no route from start point ({}) to end point ({}).'.format(points[i].toString(), endPoint.toString()))
feedback.setProgressText(msg)
QgsMessageLog.logMessage(msg, self.tr('Processing'), QgsMessageLog.WARNING)
continue
cost = 0.0
current = idxEnd
while current != idxStart:
cost += graph.edge(tree[current]).cost(0)
route.append(graph.vertex(graph.edge(tree[current]).inVertex()).point())
current = graph.edge(tree[current]).outVertex()
route.append(snappedPoints[i])
route.reverse()
geom = QgsGeometry.fromPolyline(route)
feat.setGeometry(geom)
feat['start'] = points[i].toString()
feat['end'] = endPoint.toString()
feat['cost'] = cost / multiplier
sink.addFeature(feat, QgsFeatureSink.FastInsert)
route[:] = []
feedback.setProgress(int(i * total))
return {self.OUTPUT: dest_id}
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_VECTOR))
startPoint = self.getParameterValue(self.START_POINT)
endPoints = dataobjects.getObjectFromUri(
self.getParameterValue(self.END_POINTS))
strategy = self.getParameterValue(self.STRATEGY)
directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
forwardValue = self.getParameterValue(self.VALUE_FORWARD)
backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
speedFieldName = self.getParameterValue(self.SPEED_FIELD)
defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
tolerance = self.getParameterValue(self.TOLERANCE)
fields = QgsFields()
fields.append(QgsField('start', QVariant.String, '', 254, 0))
fields.append(QgsField('end', QVariant.String, '', 254, 0))
fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
feat = QgsFeature()
feat.setFields(fields)
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(
fields.toList(),
QgsWkbTypes.LineString,
layer.crs())
tmp = startPoint.split(',')
startPoint = QgsPoint(float(tmp[0]), float(tmp[1]))
directionField = -1
if directionFieldName is not None:
directionField = layer.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName is not None:
speedField = layer.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(layer,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = iface.mapCanvas().mapSettings().destinationCrs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField,
defaultSpeed,
multiplier * 1000.0 / 3600.0)
multiplier = 3600
director.addStrategy(strategy)
builder = QgsGraphBuilder(iface.mapCanvas().mapSettings().destinationCrs(),
iface.mapCanvas().hasCrsTransformEnabled(),
tolerance)
progress.setInfo(self.tr('Loading end points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
features = vector.features(endPoints, request)
count = len(features)
points = [startPoint]
for f in features:
points.append(f.geometry().asPoint())
progress.setInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points)
progress.setInfo(self.tr('Calculating shortest paths...'))
graph = builder.graph()
idxStart = graph.findVertex(snappedPoints[0])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
route = []
total = 100.0 / count
for i in range(1, count + 1):
idxEnd = graph.findVertex(snappedPoints[i])
if tree[idxEnd] == -1:
msg = self.tr('There is no route from start point ({}) to end point ({}).'.format(startPoint.toString(), points[i].toString()))
progress.setText(msg)
ProcessingLog.addToLog(ProcessingLog.LOG_WARNING, msg)
continue
cost = 0.0
current = idxEnd
while current != idxStart:
cost += graph.edge(tree[current]).cost(0)
route.append(graph.vertex(graph.edge(tree[current]).inVertex()).point())
current = graph.edge(tree[current]).outVertex()
route.append(snappedPoints[0])
route.reverse()
geom = QgsGeometry.fromPolyline(route)
feat.setGeometry(geom)
feat['start'] = startPoint.toString()
feat['end'] = points[i].toString()
feat['cost'] = cost / multiplier
writer.addFeature(feat)
route[:] = []
progress.setPercentage(int(i * total))
del writer
def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(
self.getParameterValue(self.INPUT_VECTOR), context)
startPoint = self.getParameterValue(self.START_POINT)
endPoints = QgsProcessingUtils.mapLayerFromString(
self.getParameterValue(self.END_POINTS), context)
strategy = self.getParameterValue(self.STRATEGY)
directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
forwardValue = self.getParameterValue(self.VALUE_FORWARD)
backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
speedFieldName = self.getParameterValue(self.SPEED_FIELD)
defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
tolerance = self.getParameterValue(self.TOLERANCE)
fields = QgsFields()
fields.append(QgsField('start', QVariant.String, '', 254, 0))
fields.append(QgsField('end', QVariant.String, '', 254, 0))
fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
feat = QgsFeature()
feat.setFields(fields)
writer = self.getOutputFromName(self.OUTPUT_LAYER).getVectorWriter(
fields, QgsWkbTypes.LineString, layer.crs(), context)
tmp = startPoint.split(',')
startPoint = QgsPointXY(float(tmp[0]), float(tmp[1]))
directionField = -1
if directionFieldName is not None:
directionField = layer.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName is not None:
speedField = layer.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(layer, directionField, forwardValue,
backwardValue, bothValue,
defaultDirection)
distUnit = iface.mapCanvas().mapSettings().destinationCrs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(
distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField, defaultSpeed,
multiplier * 1000.0 / 3600.0)
multiplier = 3600
director.addStrategy(strategy)
builder = QgsGraphBuilder(
iface.mapCanvas().mapSettings().destinationCrs(), True, tolerance)
feedback.pushInfo(self.tr('Loading end points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags()
^ QgsFeatureRequest.SubsetOfAttributes)
features = QgsProcessingUtils.getFeatures(endPoints, context, request)
count = QgsProcessingUtils.featureCount(endPoints, context)
points = [startPoint]
for f in features:
points.append(f.geometry().asPoint())
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points)
feedback.pushInfo(self.tr('Calculating shortest paths...'))
graph = builder.graph()
idxStart = graph.findVertex(snappedPoints[0])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
route = []
total = 100.0 / count
for i in range(1, count + 1):
idxEnd = graph.findVertex(snappedPoints[i])
if tree[idxEnd] == -1:
msg = self.tr(
'There is no route from start point ({}) to end point ({}).'
.format(startPoint.toString(), points[i].toString()))
feedback.setProgressText(msg)
QgsMessageLog.logMessage(msg, self.tr('Processing'),
QgsMessageLog.WARNING)
continue
cost = 0.0
current = idxEnd
while current != idxStart:
cost += graph.edge(tree[current]).cost(0)
route.append(
graph.vertex(graph.edge(tree[current]).inVertex()).point())
current = graph.edge(tree[current]).outVertex()
route.append(snappedPoints[0])
route.reverse()
geom = QgsGeometry.fromPolyline(route)
feat.setGeometry(geom)
feat['start'] = startPoint.toString()
feat['end'] = points[i].toString()
feat['cost'] = cost / multiplier
writer.addFeature(feat)
route[:] = []
feedback.setProgress(int(i * total))
del writer
def processAlgorithm(self, feedback):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_VECTOR))
startPoints = dataobjects.getObjectFromUri(
self.getParameterValue(self.START_POINTS))
strategy = self.getParameterValue(self.STRATEGY)
travelCost = self.getParameterValue(self.TRAVEL_COST)
directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
forwardValue = self.getParameterValue(self.VALUE_FORWARD)
backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
speedFieldName = self.getParameterValue(self.SPEED_FIELD)
defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
tolerance = self.getParameterValue(self.TOLERANCE)
fields = QgsFields()
fields.append(QgsField('type', QVariant.String, '', 254, 0))
fields.append(QgsField('start', QVariant.String, '', 254, 0))
feat = QgsFeature()
feat.setFields(fields)
writerPoints = self.getOutputFromName(
self.OUTPUT_POINTS).getVectorWriter(fields, QgsWkbTypes.MultiPoint,
layer.crs())
writerPolygons = self.getOutputFromName(
self.OUTPUT_POLYGON).getVectorWriter(fields, QgsWkbTypes.Polygon,
layer.crs())
directionField = -1
if directionFieldName is not None:
directionField = layer.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName is not None:
speedField = layer.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(layer, directionField, forwardValue,
backwardValue, bothValue,
defaultDirection)
distUnit = iface.mapCanvas().mapSettings().destinationCrs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(
distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField, defaultSpeed,
multiplier * 1000.0 / 3600.0)
director.addStrategy(strategy)
builder = QgsGraphBuilder(
iface.mapCanvas().mapSettings().destinationCrs(),
iface.mapCanvas().hasCrsTransformEnabled(), tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags()
^ QgsFeatureRequest.SubsetOfAttributes)
features = vector.features(startPoints, request)
points = []
for f in features:
points.append(f.geometry().asPoint())
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points)
feedback.pushInfo(self.tr('Calculating service areas...'))
graph = builder.graph()
vertices = []
upperBoundary = []
lowerBoundary = []
total = 100.0 / len(snappedPoints)
for i, p in enumerate(snappedPoints):
idxStart = graph.findVertex(snappedPoints[i])
origPoint = points[i].toString()
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
for j, v in enumerate(cost):
if v > travelCost and tree[j] != -1:
vertexId = graph.edge(tree[j]).outVertex()
if cost[vertexId] <= travelCost:
vertices.append(j)
for j in vertices:
upperBoundary.append(
graph.vertex(graph.edge(tree[j]).inVertex()).point())
lowerBoundary.append(
graph.vertex(graph.edge(tree[j]).outVertex()).point())
geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
feat.setGeometry(geomUpper)
feat['type'] = 'upper'
feat['start'] = origPoint
writerPoints.addFeature(feat)
feat.setGeometry(geomLower)
feat['type'] = 'lower'
feat['start'] = origPoint
writerPoints.addFeature(feat)
upperBoundary.append(startPoint)
lowerBoundary.append(startPoint)
geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
geom = geomUpper.convexHull()
feat.setGeometry(geom)
feat['type'] = 'upper'
feat['start'] = origPoint
writerPolygons.addFeature(feat)
geom = geomLower.convexHull()
feat.setGeometry(geom)
feat['type'] = 'lower'
feat['start'] = origPoint
writerPolygons.addFeature(feat)
vertices[:] = []
upperBoundary[:] = []
lowerBoundary[:] = []
feedback.setProgress(int(i * total))
del writerPoints
del writerPolygons
def processAlgorithm(self, feedback):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_VECTOR))
startPoints = dataobjects.getObjectFromUri(
self.getParameterValue(self.START_POINTS))
strategy = self.getParameterValue(self.STRATEGY)
travelCost = self.getParameterValue(self.TRAVEL_COST)
directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
forwardValue = self.getParameterValue(self.VALUE_FORWARD)
backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
speedFieldName = self.getParameterValue(self.SPEED_FIELD)
defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
tolerance = self.getParameterValue(self.TOLERANCE)
fields = QgsFields()
fields.append(QgsField('type', QVariant.String, '', 254, 0))
fields.append(QgsField('start', QVariant.String, '', 254, 0))
feat = QgsFeature()
feat.setFields(fields)
writerPoints = self.getOutputFromName(
self.OUTPUT_POINTS).getVectorWriter(
fields,
QgsWkbTypes.MultiPoint,
layer.crs())
writerPolygons = self.getOutputFromName(
self.OUTPUT_POLYGON).getVectorWriter(
fields,
QgsWkbTypes.Polygon,
layer.crs())
directionField = -1
if directionFieldName is not None:
directionField = layer.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName is not None:
speedField = layer.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(layer,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = iface.mapCanvas().mapSettings().destinationCrs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField,
defaultSpeed,
multiplier * 1000.0 / 3600.0)
director.addStrategy(strategy)
builder = QgsGraphBuilder(iface.mapCanvas().mapSettings().destinationCrs(),
iface.mapCanvas().hasCrsTransformEnabled(),
tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
features = vector.features(startPoints, request)
points = []
for f in features:
points.append(f.geometry().asPoint())
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points)
feedback.pushInfo(self.tr('Calculating service areas...'))
graph = builder.graph()
vertices = []
upperBoundary = []
lowerBoundary = []
total = 100.0 / len(snappedPoints)
for i, p in enumerate(snappedPoints):
idxStart = graph.findVertex(snappedPoints[i])
origPoint = points[i].toString()
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
for j, v in enumerate(cost):
if v > travelCost and tree[j] != -1:
vertexId = graph.edge(tree[j]).outVertex()
if cost[vertexId] <= travelCost:
vertices.append(j)
for j in vertices:
upperBoundary.append(graph.vertex(graph.edge(tree[j]).inVertex()).point())
lowerBoundary.append(graph.vertex(graph.edge(tree[j]).outVertex()).point())
geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
feat.setGeometry(geomUpper)
feat['type'] = 'upper'
feat['start'] = origPoint
writerPoints.addFeature(feat)
feat.setGeometry(geomLower)
feat['type'] = 'lower'
feat['start'] = origPoint
writerPoints.addFeature(feat)
upperBoundary.append(startPoint)
lowerBoundary.append(startPoint)
geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
geom = geomUpper.convexHull()
feat.setGeometry(geom)
feat['type'] = 'upper'
feat['start'] = origPoint
writerPolygons.addFeature(feat)
geom = geomLower.convexHull()
feat.setGeometry(geom)
feat['type'] = 'lower'
feat['start'] = origPoint
writerPolygons.addFeature(feat)
vertices[:] = []
upperBoundary[:] = []
lowerBoundary[:] = []
feedback.setProgress(int(i * total))
del writerPoints
del writerPolygons
def processAlgorithm(self, parameters, context, feedback):
network = self.parameterAsSource(parameters, self.INPUT, context)
startPoints = self.parameterAsSource(parameters, self.START_POINTS,
context)
strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
travelCost = self.parameterAsDouble(parameters, self.TRAVEL_COST,
context)
directionFieldName = self.parameterAsString(parameters,
self.DIRECTION_FIELD,
context)
forwardValue = self.parameterAsString(parameters, self.VALUE_FORWARD,
context)
backwardValue = self.parameterAsString(parameters, self.VALUE_BACKWARD,
context)
bothValue = self.parameterAsString(parameters, self.VALUE_BOTH,
context)
defaultDirection = self.parameterAsEnum(parameters,
self.DEFAULT_DIRECTION,
context)
speedFieldName = self.parameterAsString(parameters, self.SPEED_FIELD,
context)
defaultSpeed = self.parameterAsDouble(parameters, self.DEFAULT_SPEED,
context)
tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
fields = QgsFields()
fields.append(QgsField('type', QVariant.String, '', 254, 0))
fields.append(QgsField('start', QVariant.String, '', 254, 0))
feat = QgsFeature()
feat.setFields(fields)
directionField = -1
if directionFieldName:
directionField = network.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName:
speedField = network.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(network, directionField,
forwardValue, backwardValue,
bothValue, defaultDirection)
distUnit = context.project().crs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(
distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField, defaultSpeed,
multiplier * 1000.0 / 3600.0)
director.addStrategy(strategy)
builder = QgsGraphBuilder(network.sourceCrs(), True, tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags()
^ QgsFeatureRequest.SubsetOfAttributes)
request.setDestinationCrs(network.sourceCrs())
features = startPoints.getFeatures(request)
total = 100.0 / startPoints.featureCount() if startPoints.featureCount(
) else 0
points = []
for current, f in enumerate(features):
if feedback.isCanceled():
break
points.append(f.geometry().asPoint())
feedback.setProgress(int(current * total))
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points, feedback)
feedback.pushInfo(self.tr('Calculating service areas...'))
graph = builder.graph()
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT,
context, fields,
QgsWkbTypes.MultiPoint,
network.sourceCrs())
vertices = []
upperBoundary = []
lowerBoundary = []
total = 100.0 / len(snappedPoints) if snappedPoints else 1
for i, p in enumerate(snappedPoints):
if feedback.isCanceled():
break
idxStart = graph.findVertex(snappedPoints[i])
origPoint = points[i].toString()
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
for j, v in enumerate(cost):
if v > travelCost and tree[j] != -1:
vertexId = graph.edge(tree[j]).outVertex()
if cost[vertexId] <= travelCost:
vertices.append(j)
for j in vertices:
upperBoundary.append(
graph.vertex(graph.edge(tree[j]).inVertex()).point())
lowerBoundary.append(
graph.vertex(graph.edge(tree[j]).outVertex()).point())
geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
feat.setGeometry(geomUpper)
feat['type'] = 'upper'
feat['start'] = origPoint
sink.addFeature(feat, QgsFeatureSink.FastInsert)
feat.setGeometry(geomLower)
feat['type'] = 'lower'
feat['start'] = origPoint
sink.addFeature(feat, QgsFeatureSink.FastInsert)
vertices[:] = []
upperBoundary[:] = []
lowerBoundary[:] = []
feedback.setProgress(int(i * total))
return {self.OUTPUT: dest_id}
def testFlags(self):
req = QgsFeatureRequest()
self.assertFalse(req.flags())
req.setFlags(QgsFeatureRequest.ExactIntersect)
self.assertEqual(req.flags(), QgsFeatureRequest.ExactIntersect)
def processAlgorithm(self, parameters, context, feedback):
network = self.parameterAsSource(parameters, self.INPUT, context)
startPoints = self.parameterAsSource(parameters, self.START_POINTS, context)
strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
travelCost = self.parameterAsDouble(parameters, self.TRAVEL_COST, context)
directionFieldName = self.parameterAsString(parameters, self.DIRECTION_FIELD, context)
forwardValue = self.parameterAsString(parameters, self.VALUE_FORWARD, context)
backwardValue = self.parameterAsString(parameters, self.VALUE_BACKWARD, context)
bothValue = self.parameterAsString(parameters, self.VALUE_BOTH, context)
defaultDirection = self.parameterAsEnum(parameters, self.DEFAULT_DIRECTION, context)
speedFieldName = self.parameterAsString(parameters, self.SPEED_FIELD, context)
defaultSpeed = self.parameterAsDouble(parameters, self.DEFAULT_SPEED, context)
tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
fields = QgsFields()
fields.append(QgsField('type', QVariant.String, '', 254, 0))
fields.append(QgsField('start', QVariant.String, '', 254, 0))
feat = QgsFeature()
feat.setFields(fields)
directionField = -1
if directionFieldName:
directionField = network.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName:
speedField = network.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(network,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = context.project().crs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField,
defaultSpeed,
multiplier * 1000.0 / 3600.0)
director.addStrategy(strategy)
builder = QgsGraphBuilder(network.sourceCrs(),
True,
tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
request.setDestinationCrs(network.sourceCrs())
features = startPoints.getFeatures(request)
total = 100.0 / startPoints.featureCount() if startPoints.featureCount() else 0
points = []
for current, f in enumerate(features):
if feedback.isCanceled():
break
points.append(f.geometry().asPoint())
feedback.setProgress(int(current * total))
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points, feedback)
feedback.pushInfo(self.tr('Calculating service areas...'))
graph = builder.graph()
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.MultiPoint, network.sourceCrs())
vertices = []
upperBoundary = []
lowerBoundary = []
total = 100.0 / len(snappedPoints) if snappedPoints else 1
for i, p in enumerate(snappedPoints):
if feedback.isCanceled():
break
idxStart = graph.findVertex(snappedPoints[i])
origPoint = points[i].toString()
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
for j, v in enumerate(cost):
if v > travelCost and tree[j] != -1:
vertexId = graph.edge(tree[j]).outVertex()
if cost[vertexId] <= travelCost:
vertices.append(j)
for j in vertices:
upperBoundary.append(graph.vertex(graph.edge(tree[j]).inVertex()).point())
lowerBoundary.append(graph.vertex(graph.edge(tree[j]).outVertex()).point())
geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
feat.setGeometry(geomUpper)
feat['type'] = 'upper'
feat['start'] = origPoint
sink.addFeature(feat, QgsFeatureSink.FastInsert)
feat.setGeometry(geomLower)
feat['type'] = 'lower'
feat['start'] = origPoint
sink.addFeature(feat, QgsFeatureSink.FastInsert)
vertices[:] = []
upperBoundary[:] = []
lowerBoundary[:] = []
feedback.setProgress(int(i * total))
return {self.OUTPUT: dest_id}
def processAlgorithm(self, parameters, context, feedback):
network = self.parameterAsSource(parameters, self.INPUT, context)
startPoints = self.parameterAsSource(parameters, self.START_POINTS, context)
endPoint = self.parameterAsPoint(parameters, self.END_POINT, context, network.sourceCrs())
strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
directionFieldName = self.parameterAsString(parameters, self.DIRECTION_FIELD, context)
forwardValue = self.parameterAsString(parameters, self.VALUE_FORWARD, context)
backwardValue = self.parameterAsString(parameters, self.VALUE_BACKWARD, context)
bothValue = self.parameterAsString(parameters, self.VALUE_BOTH, context)
defaultDirection = self.parameterAsEnum(parameters, self.DEFAULT_DIRECTION, context)
speedFieldName = self.parameterAsString(parameters, self.SPEED_FIELD, context)
defaultSpeed = self.parameterAsDouble(parameters, self.DEFAULT_SPEED, context)
tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
fields = QgsFields()
fields.append(QgsField('start', QVariant.String, '', 254, 0))
fields.append(QgsField('end', QVariant.String, '', 254, 0))
fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
feat = QgsFeature()
feat.setFields(fields)
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.LineString, network.sourceCrs())
directionField = -1
if directionFieldName:
directionField = network.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName:
speedField = network.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(network,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = context.project().crs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField,
defaultSpeed,
multiplier * 1000.0 / 3600.0)
multiplier = 3600
director.addStrategy(strategy)
builder = QgsGraphBuilder(network.sourceCrs(),
True,
tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
request.setDestinationCrs(network.sourceCrs())
features = startPoints.getFeatures(request)
total = 100.0 / startPoints.featureCount() if startPoints.featureCount() else 0
points = [endPoint]
for current, f in enumerate(features):
if feedback.isCanceled():
break
points.append(f.geometry().asPoint())
feedback.setProgress(int(current * total))
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points, feedback)
feedback.pushInfo(self.tr('Calculating shortest paths...'))
graph = builder.graph()
idxEnd = graph.findVertex(snappedPoints[0])
route = []
nPoints = len(snappedPoints)
total = 100.0 / nPoints if nPoints else 1
for i in range(1, nPoints + 1):
if feedback.isCanceled():
break
idxStart = graph.findVertex(snappedPoints[i])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
if tree[idxEnd] == -1:
msg = self.tr('There is no route from start point ({}) to end point ({}).'.format(points[i].toString(), endPoint.toString()))
feedback.setProgressText(msg)
QgsMessageLog.logMessage(msg, self.tr('Processing'), QgsMessageLog.WARNING)
continue
cost = 0.0
current = idxEnd
while current != idxStart:
cost += graph.edge(tree[current]).cost(0)
route.append(graph.vertex(graph.edge(tree[current]).inVertex()).point())
current = graph.edge(tree[current]).outVertex()
route.append(snappedPoints[i])
route.reverse()
geom = QgsGeometry.fromPolylineXY(route)
feat.setGeometry(geom)
feat['start'] = points[i].toString()
feat['end'] = endPoint.toString()
feat['cost'] = cost / multiplier
sink.addFeature(feat, QgsFeatureSink.FastInsert)
route[:] = []
feedback.setProgress(int(i * total))
return {self.OUTPUT: dest_id}
def layerToVolumeTxt(layer, project):
''' extract layer column to have only traffic count for the algoritm
This utility is intended to generate v_traffic.txt
Column of the layer are get from the project. If a column is not specified
it will filled with 0 value
'''
# get out filename
confFileName = project.fileName()
projectPath = os.path.dirname(confFileName)
outFileName = project.value('General.InputFileDefinition/TrafficVolume',
'')
if not outFileName:
raise Exception(
'No General.InputFileDefinition/TrafficVolume filename has bee specified'
)
if not os.path.isabs(outFileName):
outFileName = os.path.join(projectPath, outFileName)
# get columns to estract
columnRoadType = project.value('InputNetwork/columnRoadType', '')
columnRoadLenght = project.value('InputNetwork/columnRoadLenght', '')
columnRoadSlope = project.value('InputNetwork/columnRoadSlope', '')
columnPassengerCars = project.value(
'VehicleCountSpeed/columnPassengerCars', '')
columnLightDutyVehicle = project.value(
'VehicleCountSpeed/columnLightDutyVehicle', '')
columnHeavyDutyVechicle = project.value(
'VehicleCountSpeed/columnHeavyDutyVechicle', '')
columnUrbanBuses = project.value('VehicleCountSpeed/columnUrbanBuses', '')
columnMotorcycle = project.value('VehicleCountSpeed/columnMotorcycle', '')
columnCouch = project.value('VehicleCountSpeed/columnCouch', '')
columnAverageSpeed = project.value('VehicleCountSpeed/columnAverageSpeed',
'')
fields = [
'id', columnRoadType, columnPassengerCars, columnLightDutyVehicle,
columnHeavyDutyVechicle, columnUrbanBuses, columnCouch,
columnMotorcycle, columnAverageSpeed, columnRoadLenght, columnRoadSlope
]
# create out file
with open(outFileName, 'w') as outFile:
# print header
template = '{}\t{}\t{}\t{}\t{}\t{}\t{}\t{}\t{}\t{:.5f}\t{:.5f}'
header = 'ID\tTYPE\tPC\tLDV\tHDV\tBUS\tCOACHES\tMOTO\tSPEED\tLENGHT\tGRAD'
print(header, file=outFile)
# get all records
fieldsToRetrieve = [x for x in fields
if x] # remove not requested fields
request = QgsFeatureRequest()
request.setSubsetOfAttributes(fieldsToRetrieve, layer.pendingFields())
request.setFlags(request.flags() | QgsFeatureRequest.NoGeometry)
for feature in layer.getFeatures(request):
values = []
for field in fields:
value = 0 # defauklt value in case the column is not present or not requested
try:
value = feature.attribute(field)
except:
pass
values.append(value)
# then print feature
print(template.format(*values), file=outFile)
def response_data_mode(self, request, export_features=False):
"""
Query layer and return data
:param request: DjangoREST API request object
:param formatter: Boolean, default False, True for to use QgsJsonExport.exportFeatures method
:return: response dict data
"""
# Create the QGIS feature request, it will be passed through filters
# and to the final QGIS API get features call.
qgis_feature_request = QgsFeatureRequest()
# Prepare arguments for the get feature call
kwargs = {}
# Apply filter backends, store original subset string
original_subset_string = self.metadata_layer.qgis_layer.subsetString()
if hasattr(self, 'filter_backends'):
try:
for backend in self.filter_backends:
backend().apply_filter(request, self.metadata_layer,
qgis_feature_request, self)
except Exception as e:
raise APIException(e)
# Paging cannot be a backend filter
if 'page' in request.query_params:
kwargs['page'] = request.query_params.get('page')
kwargs['page_size'] = request.query_params.get('page_size', 10)
# Make sure we have all attrs we need to build the server FID
provider = self.metadata_layer.qgis_layer.dataProvider()
if qgis_feature_request.flags() & QgsFeatureRequest.SubsetOfAttributes:
attrs = qgis_feature_request.subsetOfAttributes()
for attr_idx in provider.pkAttributeIndexes():
if attr_idx not in attrs:
attrs.append(attr_idx)
qgis_feature_request.setSubsetOfAttributes(attrs)
self.features = get_qgis_features(self.metadata_layer.qgis_layer,
qgis_feature_request, **kwargs)
# Reproject feature if layer CRS != Project CRS
if self.reproject:
for f in self.features:
self.reproject_feature(f)
ex = QgsJsonExporter(self.metadata_layer.qgis_layer)
# If 'unique' request params is set,
# api return a list of unique
# field name sent with 'unique' param.
# --------------------------------------
# IDEA: for big data it'll be iterate over features to get unique
# c++ iteration is fast. Instead memory layer with too many features can be a problem.
if 'unique' in request.query_params:
vl = QgsVectorLayer(
QgsWkbTypes.displayString(
self.metadata_layer.qgis_layer.wkbType()),
"temporary_vector", "memory")
pr = vl.dataProvider()
# add fields
pr.addAttributes(self.metadata_layer.qgis_layer.fields())
vl.updateFields(
) # tell the vector layer to fetch changes from the provider
res = pr.addFeatures(self.features)
uniques = vl.uniqueValues(
self.metadata_layer.qgis_layer.fields().indexOf(
request.query_params.get('unique')))
values = []
for u in uniques:
try:
if u:
values.append(json.loads(QgsJsonUtils.encodeValue(u)))
except Exception as e:
logger.error(f'Response vector widget unique: {e}')
continue
# sort values
values.sort()
self.results.update({'data': values, 'count': len(values)})
del (vl)
else:
ex.setTransformGeometries(False)
# check for formatter query url param and check if != 0
if 'formatter' in request.query_params:
formatter = request.query_params.get('formatter')
if formatter.isnumeric() and int(formatter) == 0:
export_features = False
else:
export_features = True
if export_features:
feature_collection = json.loads(
ex.exportFeatures(self.features))
else:
# to exclude QgsFormater used into QgsJsonExporter is necessary build by hand single json feature
ex.setIncludeAttributes(False)
feature_collection = {
'type': 'FeatureCollection',
'features': []
}
for feature in self.features:
fnames = []
date_fields = []
for f in feature.fields():
fnames.append(f.name())
if f.typeName() in ('date', 'datetime', 'time'):
date_fields.append(f)
jsonfeature = json.loads(
ex.exportFeature(
feature, dict(zip(fnames, feature.attributes()))))
# Update date and datetime fields value if widget is active
if len(date_fields) > 0:
for f in date_fields:
field_idx = self.metadata_layer.qgis_layer.fields(
).indexFromName(f.name())
options = self.metadata_layer.qgis_layer.editorWidgetSetup(
field_idx).config()
if 'field_iso_format' in options and not options[
'field_iso_format']:
try:
jsonfeature['properties'][f.name()] = feature.attribute(f.name())\
.toString(options['field_format'])
except:
pass
feature_collection['features'].append(jsonfeature)
# Change media
self.change_media(feature_collection)
# Patch feature IDs with server featureIDs
fids_map = {}
for f in self.features:
fids_map[f.id()] = server_fid(f, provider)
for i in range(len(feature_collection['features'])):
f = feature_collection['features'][i]
f['id'] = fids_map[f['id']]
self.results.update(
APIVectorLayerStructure(
**{
'data':
feature_collection,
'count':
count_qgis_features(self.metadata_layer.qgis_layer,
qgis_feature_request, **kwargs),
'geometryType':
self.metadata_layer.geometry_type,
}).as_dict())
# FIXME: add extra fields data by signals and receivers
# FIXME: featurecollection = post_serialize_maplayer.send(layer_serializer, layer=self.layer_name)
# FIXME: Not sure how to map this to the new QGIS API
# Restore the original subset string
self.metadata_layer.qgis_layer.setSubsetString(original_subset_string)
def layerToVolumeTxt(layer, project):
''' extract layer column to have only traffic count for the algoritm
This utility is intended to generate v_traffic.txt
Column of the layer are get from the project. If a column is not specified
it will filled with 0 value
'''
# get out filename
confFileName = project.fileName()
projectPath = os.path.dirname(confFileName)
outFileName = project.value('General.InputFileDefinition/TrafficVolume', '')
if not outFileName:
raise Exception('No General.InputFileDefinition/TrafficVolume filename has bee specified')
if not os.path.isabs( outFileName ):
outFileName = os.path.join(projectPath, outFileName)
# get columns to estract
columnRoadType = project.value('InputNetwork/columnRoadType', '')
columnRoadLenght = project.value('InputNetwork/columnRoadLenght', '')
columnRoadSlope = project.value('InputNetwork/columnRoadSlope', '')
columnPassengerCars = project.value('VehicleCountSpeed/columnPassengerCars', '')
columnLightDutyVehicle = project.value('VehicleCountSpeed/columnLightDutyVehicle', '')
columnHeavyDutyVechicle = project.value('VehicleCountSpeed/columnHeavyDutyVechicle', '')
columnUrbanBuses = project.value('VehicleCountSpeed/columnUrbanBuses', '')
columnMotorcycle = project.value('VehicleCountSpeed/columnMotorcycle', '')
columnCouch = project.value('VehicleCountSpeed/columnCouch', '')
columnAverageSpeed = project.value('VehicleCountSpeed/columnAverageSpeed', '')
fields = ['id',
columnRoadType,
columnPassengerCars,
columnLightDutyVehicle,
columnHeavyDutyVechicle,
columnUrbanBuses,
columnCouch,
columnMotorcycle,
columnAverageSpeed,
columnRoadLenght,
columnRoadSlope
]
# create out file
with open(outFileName, 'w') as outFile:
# print header
template = '{}\t{}\t{}\t{}\t{}\t{}\t{}\t{}\t{}\t{:.5f}\t{:.5f}'
header = 'ID\tTYPE\tPC\tLDV\tHDV\tBUS\tCOACHES\tMOTO\tSPEED\tLENGHT\tGRAD'
print(header, file=outFile)
# get all records
fieldsToRetrieve = [x for x in fields if x] # remove not requested fields
request = QgsFeatureRequest()
request.setSubsetOfAttributes(fieldsToRetrieve, layer.pendingFields())
request.setFlags( request.flags() | QgsFeatureRequest.NoGeometry)
for feature in layer.getFeatures( request ):
values = []
for field in fields:
value = 0 # defauklt value in case the column is not present or not requested
try:
value = feature.attribute(field)
except:
pass
values.append( value )
# then print feature
print(template.format(*values), file=outFile)
