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[PROCESSING] Speed up dissolve without changing parameters

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This commit is contained in:
Bernhard Ströbl 2015-11-11 16:20:59 +01:00
parent 04abaf3bfa
commit cfb932afa9
1 changed files with 47 additions and 35 deletions
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82
python/plugins/processing/algs/qgis/Dissolve.py
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@ -52,22 +52,22 @@ class Dissolve(GeoAlgorithm):
fieldname = self.getParameterValue(Dissolve.FIELD)
vlayerA = dataobjects.getObjectFromUri(
self.getParameterValue(Dissolve.INPUT))
field = vlayerA.fieldNameIndex(fieldname)
vproviderA = vlayerA.dataProvider()
fields = vproviderA.fields()
fields = vlayerA.fields()
writer = self.getOutputFromName(
Dissolve.OUTPUT).getVectorWriter(fields,
vproviderA.geometryType(),
vproviderA.crs())
outFeat = QgsFeature()
nElement = 0
nFeat = vproviderA.featureCount()
features = vector.features(vlayerA)
nFeat = len(features)
if not useField:
first = True
features = vector.features(vlayerA)
for inFeat in features:
nElement += 1
progress.setPercentage(int(nElement / nFeat * 100))
progress.setPercentage(int(nElement * 100 / nFeat))
if first:
attrs = inFeat.attributes()
tmpInGeom = QgsGeometry(inFeat.geometry())
@ -85,37 +85,49 @@ class Dissolve(GeoAlgorithm):
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
else:
unique = vector.getUniqueValues(vlayerA, int(field))
nFeat = nFeat * len(unique)
fieldIdx = vlayerA.fieldNameIndex(fieldname)
unique = vector.getUniqueValues(vlayerA, int(fieldIdx))
nFeat = len(unique)
myDict = {}
attrDict = {}
for item in unique:
first = True
add = True
features = vector.features(vlayerA)
for inFeat in features:
nElement += 1
progress.setPercentage(int(nElement / nFeat * 100))
atMap = inFeat.attributes()
tempItem = atMap[field]
if unicode(tempItem).strip() == unicode(item).strip():
if first:
QgsGeometry(inFeat.geometry())
tmpInGeom = QgsGeometry(inFeat.geometry())
outFeat.setGeometry(tmpInGeom)
first = False
attrs = inFeat.attributes()
else:
tmpInGeom = QgsGeometry(inFeat.geometry())
tmpOutGeom = QgsGeometry(outFeat.geometry())
try:
tmpOutGeom = QgsGeometry(
tmpOutGeom.combine(tmpInGeom))
outFeat.setGeometry(tmpOutGeom)
except:
raise GeoAlgorithmExecutionException(
self.tr('Geometry exception while dissolving'))
if add:
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
myDict[unicode(item).strip()] = []
attrDict[unicode(item).strip()] = None
unique = None
for inFeat in features:
attrs = inFeat.attributes()
tempItem = attrs[fieldIdx]
tmpInGeom = QgsGeometry(inFeat.geometry())
if attrDict[unicode(tempItem).strip()] == None:
# keep attributes of first feature
attrDict[unicode(tempItem).strip()] = attrs
myDict[unicode(tempItem).strip()].append(tmpInGeom)
features = None
for key, value in myDict.items():
nElement += 1
progress.setPercentage(int(nElement * 100 / nFeat))
for i in range(len(value)):
tmpInGeom = value[i]
if i == 0:
tmpOutGeom = tmpInGeom
else:
try:
tmpOutGeom = QgsGeometry(
tmpOutGeom.combine(tmpInGeom))
except:
raise GeoAlgorithmExecutionException(
self.tr('Geometry exception while dissolving'))
outFeat.setGeometry(tmpOutGeom)
outFeat.setAttributes(attrDict[key])
writer.addFeature(outFeat)
del writer
def defineCharacteristics(self):