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ede452be85
Algorithms are now passed a QgsProcessingFeedback object instead of the loosely defined progress parameter.
127 lines
5.2 KiB
Python
127 lines
5.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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GeometryByExpression.py
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-----------------------
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Date : October 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson 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__ = 'Nyall Dawson'
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__date__ = 'October 2016'
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__copyright__ = '(C) 2016, Nyall Dawson'
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# This will get replaced with a git SHA1 when you do a git archive323
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__revision__ = '$Format:%H$'
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from qgis.core import QgsWkbTypes, QgsExpression, QgsExpressionContext, QgsExpressionContextUtils, QgsGeometry
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from processing.core.ProcessingLog import ProcessingLog
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from processing.core.parameters import ParameterVector, ParameterSelection, ParameterBoolean, ParameterExpression
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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class GeometryByExpression(GeoAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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OUTPUT_GEOMETRY = 'OUTPUT_GEOMETRY'
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WITH_Z = 'WITH_Z'
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WITH_M = 'WITH_M'
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EXPRESSION = 'EXPRESSION'
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Geometry by expression')
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self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
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self.addParameter(ParameterVector(self.INPUT_LAYER,
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self.tr('Input layer')))
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self.geometry_types = [self.tr('Polygon'),
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'Line',
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'Point']
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self.addParameter(ParameterSelection(
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self.OUTPUT_GEOMETRY,
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self.tr('Output geometry type'),
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self.geometry_types, default=0))
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self.addParameter(ParameterBoolean(self.WITH_Z,
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self.tr('Output geometry has z dimension'), False))
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self.addParameter(ParameterBoolean(self.WITH_M,
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self.tr('Output geometry has m values'), False))
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self.addParameter(ParameterExpression(self.EXPRESSION,
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self.tr("Geometry expression"), '$geometry', parent_layer=self.INPUT_LAYER))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Modified geometry')))
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def processAlgorithm(self, feedback):
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT_LAYER))
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geometry_type = self.getParameterValue(self.OUTPUT_GEOMETRY)
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wkb_type = None
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if geometry_type == 0:
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wkb_type = QgsWkbTypes.Polygon
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elif geometry_type == 1:
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wkb_type = QgsWkbTypes.LineString
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else:
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wkb_type = QgsWkbTypes.Point
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if self.getParameterValue(self.WITH_Z):
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wkb_type = QgsWkbTypes.addZ(wkb_type)
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if self.getParameterValue(self.WITH_M):
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wkb_type = QgsWkbTypes.addM(wkb_type)
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writer = self.getOutputFromName(
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self.OUTPUT_LAYER).getVectorWriter(
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layer.fields(),
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wkb_type,
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layer.crs())
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expression = QgsExpression(self.getParameterValue(self.EXPRESSION))
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if expression.hasParserError():
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raise GeoAlgorithmExecutionException(expression.parserErrorString())
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exp_context = QgsExpressionContext(QgsExpressionContextUtils.globalProjectLayerScopes(layer))
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if not expression.prepare(exp_context):
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raise GeoAlgorithmExecutionException(
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self.tr('Evaluation error: %s' % expression.evalErrorString()))
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features = vector.features(layer)
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total = 100.0 / len(features)
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for current, input_feature in enumerate(features):
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output_feature = input_feature
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exp_context.setFeature(input_feature)
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value = expression.evaluate(exp_context)
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if expression.hasEvalError():
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raise GeoAlgorithmExecutionException(
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self.tr('Evaluation error: %s' % expression.evalErrorString()))
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if not value:
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output_feature.setGeometry(QgsGeometry())
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else:
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if not isinstance(value, QgsGeometry):
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raise GeoAlgorithmExecutionException(
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self.tr('{} is not a geometry').format(value))
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output_feature.setGeometry(value)
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writer.addFeature(output_feature)
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feedback.setProgress(int(current * total))
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del writer
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