def test_ValidFeature(self):
myPath = os.path.join(unitTestDataPath(), 'points.shp')
myLayer = QgsVectorLayer(myPath, 'Points', 'ogr')
provider = myLayer.dataProvider()
allAttrs = provider.attributeIndexes()
myLayer.select(allAttrs)
feat = QgsFeature()
myLayer.nextFeature(feat)
myValidValue = feat.isValid()
myMessage = '\nExpected: %s\nGot: %s' % ("True", myValidValue)
assert myValidValue == True, myMessage
def test_Attributes(self):
myPath = os.path.join(unitTestDataPath(), 'lines.shp')
myLayer = QgsVectorLayer(myPath, 'Lines', 'ogr')
provider = myLayer.dataProvider()
allAttrs = provider.attributeIndexes()
myLayer.select(allAttrs)
feat = QgsFeature()
myLayer.nextFeature(feat)
myAttributes = feat.attributes()
myExpectedAttributes = [ QVariant("Highway"), QVariant(1) ]
# Only for printing purposes
myAttributeDict = [
str(myAttributes[0].toString()),
int(myAttributes[1].toString()) ]
myExpectedAttributes = [ "Highway", 1 ]
myMessage = '\nExpected: %s\nGot: %s' % (myExpectedAttributes,
myAttributes)
assert myAttributes == myExpectedAttributes, myMessage
def testClipping(self):
"""Test that we can clip geometries using other geometries."""
myMemoryLayer = QgsVectorLayer(
('LineString?crs=epsg:4326&field=name:string(20)&index=yes'),
'clip-in',
'memory')
assert myMemoryLayer is not None, 'Provider not initialised'
myProvider = myMemoryLayer.dataProvider()
assert myProvider is not None
myFeature1 = QgsFeature()
myFeature1.setGeometry(QgsGeometry.fromPolyline([
QgsPoint(10,10),
QgsPoint(20,10),
QgsPoint(30,10),
QgsPoint(40,10),
]
))
myFeature1.setAttributes([QVariant('Johny')])
myFeature2 = QgsFeature()
myFeature2.setGeometry(QgsGeometry.fromPolyline([
QgsPoint(10,10),
QgsPoint(20,20),
QgsPoint(30,30),
QgsPoint(40,40),
]
))
myFeature2.setAttributes([QVariant('Be')])
myFeature3 = QgsFeature()
myFeature3.setGeometry(QgsGeometry.fromPolyline([
QgsPoint(10,10),
QgsPoint(10,20),
QgsPoint(10,30),
QgsPoint(10,40),
]
))
myFeature3.setAttributes([QVariant('Good')])
myResult, myFeatures = myProvider.addFeatures(
[myFeature1, myFeature2, myFeature3])
assert myResult == True
assert len(myFeatures) == 3
myClipPolygon = QgsGeometry.fromPolygon([[
QgsPoint(20,20),
QgsPoint(20,30),
QgsPoint(30,30),
QgsPoint(30,20),
QgsPoint(20,20),
]]
)
print 'Clip: %s' % myClipPolygon.exportToWkt()
writeShape(myMemoryLayer, 'clipGeometryBefore.shp')
myMemoryLayer.select(myProvider.attributeIndexes())
myFeatures = []
myFeature = QgsFeature()
while myMemoryLayer.nextFeature(myFeature):
myGeometry = myFeature.geometry()
if myGeometry.intersects(myClipPolygon):
# Adds nodes where the clip and the line intersec
myCombinedGeometry = myGeometry.combine(myClipPolygon)
# Gives you the areas inside the clip
mySymmetricalGeometry = myGeometry.symDifference(
myCombinedGeometry)
# Gives you areas outside the clip area
# myDifferenceGeometry = myCombinedGeometry.difference(
# myClipPolygon)
#print 'Original: %s' % myGeometry.exportToWkt()
#print 'Combined: %s' % myCombinedGeometry.exportToWkt()
#print 'Difference: %s' % myDifferenceGeometry.exportToWkt()
print 'Symmetrical: %s' % mySymmetricalGeometry.exportToWkt()
myExpectedWkt = 'LINESTRING(20.0 20.0, 30.0 30.0)'
# There should only be one feature that intersects this clip
# poly so this assertion should work.
self.assertEqual(myExpectedWkt,
mySymmetricalGeometry.exportToWkt())
myNewFeature = QgsFeature()
myNewFeature.setAttributes(myFeature.attributes())
myNewFeature.setGeometry(mySymmetricalGeometry)
myFeatures.append(myNewFeature)
myNewMemoryLayer = QgsVectorLayer(
('LineString?crs=epsg:4326&field=name:string(20)&index=yes'),
'clip-out',
'memory')
myNewProvider = myNewMemoryLayer.dataProvider()
myResult, myFeatures = myNewProvider.addFeatures(myFeatures)
self.assertTrue(myResult)
self.assertEqual(len(myFeatures), 1)
writeShape(myNewMemoryLayer, 'clipGeometryAfter.shp')
