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[PROCESSING] Speed up dissolve (esp. when using dissolve field)

Change parameters to have a more consistent UI
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bstroebl authored and m-kuhn committed Sep 11, 2015
1 parent 14f84d1 commit 116089e6ec0bd9bfd15395206bd6e880561da859
Showing with 52 additions and 39 deletions.
  1. +52 −39 python/plugins/processing/algs/qgis/Dissolve.py
@@ -25,11 +25,11 @@

__revision__ = '$Format:%H$'

from qgis.core import QgsFeature, QgsGeometry
from PyQt4.QtCore import QVariant
from qgis.core import QgsFeature, QgsGeometry, QgsField, QgsFields
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterBoolean
from processing.core.parameters import ParameterTableField
from processing.core.outputs import OutputVector
from processing.tools import vector, dataobjects
@@ -40,26 +40,34 @@ class Dissolve(GeoAlgorithm):
INPUT = 'INPUT'
OUTPUT = 'OUTPUT'
FIELD = 'FIELD'
DISSOLVE_ALL = 'DISSOLVE_ALL'

#==========================================================================
#def getIcon(self):
# return QtGui.QIcon(os.path.dirname(__file__) + "/icons/dissolve.png")
#==========================================================================

def processAlgorithm(self, progress):
useField = not self.getParameterValue(Dissolve.DISSOLVE_ALL)
fieldname = self.getParameterValue(Dissolve.FIELD)
vlayerA = dataobjects.getObjectFromUri(
self.getParameterValue(Dissolve.INPUT))
field = vlayerA.fieldNameIndex(fieldname)
vproviderA = vlayerA.dataProvider()
fields = vproviderA.fields()
fields = QgsFields()
fieldname = self.getParameterValue(Dissolve.FIELD)
try:
fieldIdx = vlayerA.fieldNameIndex(fieldname)
field = vlayerA.fields().field(fieldname)
fields.append(field)
useField = True
except:
useField = False

countField = QgsField("count", QVariant.Int, '', 10, 0)
fields.append(countField)
writer = self.getOutputFromName(
Dissolve.OUTPUT).getVectorWriter(fields,
vproviderA.geometryType(),
vproviderA.crs())
outFeat = QgsFeature()
outFeat.initAttributes(fields.count())
nElement = 0
nFeat = vlayerA.selectedFeatureCount()

@@ -73,53 +81,59 @@ def processAlgorithm(self, progress):
nElement += 1
progress.setPercentage(int(nElement * 100 / nFeat))
if first:
attrs = inFeat.attributes()
tmpInGeom = QgsGeometry(inFeat.geometry())
outFeat.setGeometry(tmpInGeom)
tmpOutGeom = QgsGeometry(inFeat.geometry())
first = False
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'))
outFeat.setAttributes(attrs)
outFeat.setGeometry(tmpOutGeom)
outFeat[0] = nElement
writer.addFeature(outFeat)
else:
unique = vector.getUniqueValues(vlayerA, int(field))
nFeat = nFeat * len(unique)
unique = vector.getUniqueValues(vlayerA, int(fieldIdx))
nFeat = len(unique)
myDict = {}
for item in unique:
first = True
add = True
features = vector.features(vlayerA)
for inFeat in features:
nElement += 1
progress.setPercentage(int(nElement * 100 / nFeat))
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()
myDict[unicode(item).strip()] = []

features = vector.features(vlayerA)
for inFeat in features:
attrs = inFeat.attributes()
tempItem = attrs[fieldIdx]
tmpInGeom = QgsGeometry(inFeat.geometry())

if len(myDict[unicode(tempItem).strip()]) == 0:
myDict[unicode(tempItem).strip()].append(tempItem)

myDict[unicode(tempItem).strip()].append(tmpInGeom)

for key, value in myDict.items():
nElement += 1
progress.setPercentage(int(nElement * 100/ nFeat))
for i in range(len(value)):
if i == 0:
tempItem = value[i]
continue
else:
tmpInGeom = value[i]

if i == 1:
tmpOutGeom = tmpInGeom
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)
outFeat.setGeometry(tmpOutGeom)
outFeat[0] = tempItem
outFeat[1] = i
writer.addFeature(outFeat)
del writer

def defineCharacteristics(self):
@@ -128,8 +142,7 @@ def defineCharacteristics(self):
self.addParameter(ParameterVector(Dissolve.INPUT,
self.tr('Input layer'),
[ParameterVector.VECTOR_TYPE_POLYGON, ParameterVector.VECTOR_TYPE_LINE]))
self.addParameter(ParameterBoolean(Dissolve.DISSOLVE_ALL,
self.tr('Dissolve all (do not use field)'), True))
self.addParameter(ParameterTableField(Dissolve.FIELD,
self.tr('Unique ID field'), Dissolve.INPUT, optional=True))
self.tr('Dissolve field (if not set all features are dissolved)'),
Dissolve.INPUT, optional=True))
self.addOutput(OutputVector(Dissolve.OUTPUT, self.tr('Dissolved')))

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