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[FEATURE][processing] New extract by expression algorithm
Filters an input layer by expression
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151 additions
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- +8 −3 python/plugins/processing/algs/help/qgis.yaml
- +67 −0 python/plugins/processing/algs/qgis/ExtractByExpression.py
- +2 −1 python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
- +32 −0 python/plugins/processing/tests/testdata/expected/extract_expression.gfs
- +29 −0 python/plugins/processing/tests/testdata/expected/extract_expression.gml
- +13 −1 python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
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| # -*- coding: utf-8 -*- | ||
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| """ | ||
| *************************************************************************** | ||
| ExtractByExpression.py | ||
| --------------------- | ||
| Date : October 2016 | ||
| Copyright : (C) 2016 by Nyall Dawson | ||
| *************************************************************************** | ||
| * * | ||
| * This program is free software; you can redistribute it and/or modify * | ||
| * it under the terms of the GNU General Public License as published by * | ||
| * the Free Software Foundation; either version 2 of the License, or * | ||
| * (at your option) any later version. * | ||
| * * | ||
| *************************************************************************** | ||
| """ | ||
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| __author__ = 'Nyall Dawson' | ||
| __date__ = 'October 2016' | ||
| __copyright__ = '(C) 2016, Nyall Dawson' | ||
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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 processing | ||
| from qgis.core import QgsExpression, QgsVectorLayer, QgsFeatureRequest | ||
| from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException | ||
| from processing.core.parameters import ParameterVector | ||
| from processing.core.outputs import OutputVector | ||
| from processing.core.GeoAlgorithm import GeoAlgorithm | ||
| from processing.core.parameters import ParameterString | ||
| from processing.tools import dataobjects | ||
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| class ExtractByExpression(GeoAlgorithm): | ||
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| INPUT = 'INPUT' | ||
| EXPRESSION = 'EXPRESSION' | ||
| OUTPUT = 'OUTPUT' | ||
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| def defineCharacteristics(self): | ||
| self.name, self.i18n_name = self.trAlgorithm('Extract by expression') | ||
| self.group, self.i18n_group = self.trAlgorithm('Vector selection tools') | ||
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| self.addParameter(ParameterVector(self.INPUT, | ||
| self.tr('Input Layer'))) | ||
| self.addParameter(ParameterString(self.EXPRESSION, | ||
| self.tr("Expression"))) | ||
| self.addOutput(OutputVector(self.OUTPUT, self.tr('Extracted (expression)'))) | ||
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| def processAlgorithm(self, progress): | ||
| layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT)) | ||
| expression_string = self.getParameterValue(self.EXPRESSION) | ||
| writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(layer.fields(), layer.wkbType(), layer.crs()) | ||
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| expression = QgsExpression(expression_string) | ||
| if not expression.hasParserError(): | ||
| req = QgsFeatureRequest().setFilterExpression(expression_string) | ||
| else: | ||
| raise GeoAlgorithmExecutionException(expression.parserErrorString()) | ||
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| for f in layer.getFeatures(req): | ||
| writer.addFeature(f) | ||
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| del writer |
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| <GMLFeatureClassList> | ||
| <GMLFeatureClass> | ||
| <Name>extract_expression</Name> | ||
| <ElementPath>extract_expression</ElementPath> | ||
| <!--POLYGON--> | ||
| <GeometryType>3</GeometryType> | ||
| <SRSName>EPSG:4326</SRSName> | ||
| <DatasetSpecificInfo> | ||
| <FeatureCount>2</FeatureCount> | ||
| <ExtentXMin>4.00000</ExtentXMin> | ||
| <ExtentXMax>10.00000</ExtentXMax> | ||
| <ExtentYMin>-3.00000</ExtentYMin> | ||
| <ExtentYMax>5.00000</ExtentYMax> | ||
| </DatasetSpecificInfo> | ||
| <PropertyDefn> | ||
| <Name>name</Name> | ||
| <ElementPath>name</ElementPath> | ||
| <Type>String</Type> | ||
| <Width>5</Width> | ||
| </PropertyDefn> | ||
| <PropertyDefn> | ||
| <Name>intval</Name> | ||
| <ElementPath>intval</ElementPath> | ||
| <Type>Integer</Type> | ||
| </PropertyDefn> | ||
| <PropertyDefn> | ||
| <Name>floatval</Name> | ||
| <ElementPath>floatval</ElementPath> | ||
| <Type>Integer</Type> | ||
| </PropertyDefn> | ||
| </GMLFeatureClass> | ||
| </GMLFeatureClassList> |
| @@ -0,0 +1,29 @@ | ||
| <?xml version="1.0" encoding="utf-8" ?> | ||
| <ogr:FeatureCollection | ||
| xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | ||
| xsi:schemaLocation="" | ||
| xmlns:ogr="http://ogr.maptools.org/" | ||
| xmlns:gml="http://www.opengis.net/gml"> | ||
| <gml:boundedBy> | ||
| <gml:Box> | ||
| <gml:coord><gml:X>4</gml:X><gml:Y>-3</gml:Y></gml:coord> | ||
| <gml:coord><gml:X>10</gml:X><gml:Y>5</gml:Y></gml:coord> | ||
| </gml:Box> | ||
| </gml:boundedBy> | ||
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| <gml:featureMember> | ||
| <ogr:extract_expression fid="polys.1"> | ||
| <ogr:geometryProperty><gml:Polygon srsName="EPSG:4326"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>5,5 6,4 4,4 5,5</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></ogr:geometryProperty> | ||
| <ogr:name>Aaaaa</ogr:name> | ||
| <ogr:intval>-33</ogr:intval> | ||
| <ogr:floatval>0</ogr:floatval> | ||
| </ogr:extract_expression> | ||
| </gml:featureMember> | ||
| <gml:featureMember> | ||
| <ogr:extract_expression fid="polys.3"> | ||
| <ogr:geometryProperty><gml:Polygon srsName="EPSG:4326"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>6,1 10,1 10,-3 6,-3 6,1</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs><gml:innerBoundaryIs><gml:LinearRing><gml:coordinates>7,0 7,-2 9,-2 9,0 7,0</gml:coordinates></gml:LinearRing></gml:innerBoundaryIs></gml:Polygon></ogr:geometryProperty> | ||
| <ogr:name>ASDF</ogr:name> | ||
| <ogr:intval>0</ogr:intval> | ||
| </ogr:extract_expression> | ||
| </gml:featureMember> | ||
| </ogr:FeatureCollection> |