def testExpressionContext(self):
req = QgsFeatureRequest()
self.assertEqual(req.expressionContext().scopeCount(), 0)
context = QgsExpressionContext()
scope = QgsExpressionContextScope()
scope.setVariable('a', 6)
context.appendScope(scope)
req.setExpressionContext(context)
self.assertEqual(req.expressionContext().scopeCount(), 1)
self.assertEqual(req.expressionContext().variable('a'), 6)
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 doStart(self):
# first see if we can pull data from the predictions layer
startTime = self.datetime
endTime = self.datetime.addDays(1)
featureRequest = QgsFeatureRequest()
stationPt = QgsPointXY(self.stationFeature.geometry().vertexAt(0))
searchRect = QgsRectangle(stationPt, stationPt)
searchRect.grow(
0.01 / 60
) # in the neighborhood of .01 nm as 1/60 = 1 arc minute in this proj.
featureRequest.setFilterRect(searchRect)
# Create a time based query
ctx = featureRequest.expressionContext()
scope = QgsExpressionContextScope()
scope.setVariable('startTime', startTime)
scope.setVariable('endTime', endTime)
scope.setVariable('station', self.stationFeature['station'])
ctx.appendScope(scope)
featureRequest.setFilterExpression(
"station = @station and time >= @startTime and time < @endTime")
featureRequest.addOrderBy('time')
savedFeatureIterator = self.manager.predictionsLayer.getFeatures(
featureRequest)
savedFeatures = list(savedFeatureIterator)
if len(savedFeatures) > 0:
# We have some features, so go ahead and stash them in the layer and resolve this promise
print('{}: retrieved {} features from layer'.format(
self.stationFeature['station'], len(savedFeatures)))
self.predictions = savedFeatures
self.resolve()
else:
# The layer didn't have what we wanted, so we must request the data we need.
# At this point, the situation falls into several possible cases.
# Case 1: A Harmonic station with known flood/ebb directions. Here
# we need two requests which can simply be combined and sorted:
# 1a: EventType, i.e. slack, flood and ebb
# 1b: SpeedDirType, as velocity can be calculated by projecting along flood/ebb
#
# Case 2: A Harmonic station with unknown flood and/or ebb.
# We actually need to combine 3 requests:
# 2a: EventType
# 2b: SpeedDirType, which only provides vector magnitude/angle
# 2c: VelocityMajorType, which only provides current velocity (but for same times as 2b)
# Here we set up requests for cases 1 and 2
if self.stationFeature['type'] == 'H':
self.speedDirRequest = CurrentPredictionRequest(
self.manager, self.stationFeature, startTime, endTime,
CurrentPredictionRequest.SpeedDirectionType)
self.addDependency(self.speedDirRequest)
self.eventRequest = CurrentPredictionRequest(
self.manager, self.stationFeature, startTime, endTime,
CurrentPredictionRequest.EventType)
self.addDependency(self.eventRequest)
floodDir = self.stationFeature['meanFloodDir']
ebbDir = self.stationFeature['meanEbbDir']
if floodDir == NULL or ebbDir == NULL:
self.velocityRequest = CurrentPredictionRequest(
self.manager, self.stationFeature, startTime, endTime,
CurrentPredictionRequest.VelocityMajorType)
self.addDependency(self.velocityRequest)
else:
self.velocityRequest = None
# Case 3: A Subordinate station which only knows its events. Here we need the following:
# 3a: PredictionEventPromises for this station in a 3-day window surrounding the date of interest
# 3b: PredictionDataPromises for the reference station in the same 3-day window.
else:
self.eventPromises = []
self.refPromises = []
refStation = self.manager.getStation(
self.stationFeature['refStation'])
if refStation is None:
print("Could not find ref station {} for {}".format(
self.stationFeature['refStation'],
self.stationFeature['station']))
else:
for dayOffset in [-1, 0, 1]:
windowDate = self.localDate.addDays(dayOffset)
dataPromise = self.manager.getDataPromise(
refStation, windowDate)
self.refPromises.append(dataPromise)
self.addDependency(dataPromise)
eventPromise = self.manager.getEventPromise(
self.stationFeature, windowDate)
self.eventPromises.append(eventPromise)
self.addDependency(eventPromise)
