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99cfb8faf3
Instead we output an empty layer - this may be critical for multi-step models where there is validly no features present in a source layer
107 lines
4.1 KiB
Python
107 lines
4.1 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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Difference.py
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---------------------
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Date : August 2012
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Copyright : (C) 2012 by Victor Olaya
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Email : volayaf at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Victor Olaya'
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__date__ = 'August 2012'
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__copyright__ = '(C) 2012, Victor Olaya'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import os
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from qgis.PyQt.QtGui import QIcon
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from qgis.core import (QgsFeatureRequest,
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QgsFeature,
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QgsGeometry,
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QgsWkbTypes,
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QgsMessageLog,
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QgsProcessingUtils)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.core.parameters import ParameterVector
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from processing.core.outputs import OutputVector
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class Difference(QgisAlgorithm):
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INPUT = 'INPUT'
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OVERLAY = 'OVERLAY'
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IGNORE_INVALID = 'IGNORE_INVALID'
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OUTPUT = 'OUTPUT'
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def icon(self):
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return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'difference.png'))
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def group(self):
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return self.tr('Vector overlay tools')
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def __init__(self):
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super().__init__()
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self.addParameter(ParameterVector(Difference.INPUT,
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self.tr('Input layer')))
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self.addParameter(ParameterVector(Difference.OVERLAY,
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self.tr('Difference layer')))
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self.addOutput(OutputVector(Difference.OUTPUT, self.tr('Difference')))
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def name(self):
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return 'difference'
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def displayName(self):
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return self.tr('Difference')
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def processAlgorithm(self, parameters, context, feedback):
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layerA = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(Difference.INPUT), context)
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layerB = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(Difference.OVERLAY), context)
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geomType = QgsWkbTypes.multiType(layerA.wkbType())
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writer = self.getOutputFromName(
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Difference.OUTPUT).getVectorWriter(layerA.fields(), geomType, layerA.crs(), context)
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outFeat = QgsFeature()
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index = QgsProcessingUtils.createSpatialIndex(layerB, context)
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selectionA = QgsProcessingUtils.getFeatures(layerA, context)
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total = 100.0 / layerA.featureCount() if layerA.featureCount() else 0
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for current, inFeatA in enumerate(selectionA):
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geom = inFeatA.geometry()
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diff_geom = QgsGeometry(geom)
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attrs = inFeatA.attributes()
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intersections = index.intersects(geom.boundingBox())
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request = QgsFeatureRequest().setFilterFids(intersections).setSubsetOfAttributes([])
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for inFeatB in layerB.getFeatures(request):
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tmpGeom = inFeatB.geometry()
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if diff_geom.intersects(tmpGeom):
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diff_geom = QgsGeometry(diff_geom.difference(tmpGeom))
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try:
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outFeat.setGeometry(diff_geom)
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outFeat.setAttributes(attrs)
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writer.addFeature(outFeat)
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except:
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QgsMessageLog.logMessage(self.tr('Feature geometry error: One or more output features ignored due to invalid geometry.'), self.tr('Processing'), QgsMessageLog.WARNING)
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continue
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feedback.setProgress(int(current * total))
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del writer
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