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125 lines
4.7 KiB
Python
125 lines
4.7 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ExtractByAttribute.py
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---------------------
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Date : May 2010
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Copyright : (C) 2010 by Michael Minn
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Email : pyqgis at michaelminn 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__ = 'Michael Minn'
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__date__ = 'May 2010'
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__copyright__ = '(C) 2010, Michael Minn'
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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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from PyQt4.QtCore import *
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from qgis.core import *
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.GeoAlgorithmExecutionException import \
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GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterTableField
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from processing.core.parameters import ParameterSelection
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from processing.core.parameters import ParameterString
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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 ExtractByAttribute(GeoAlgorithm):
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INPUT = 'INPUT'
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FIELD = 'FIELD'
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OPERATOR = 'OPERATOR'
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VALUE = 'VALUE'
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OUTPUT = 'OUTPUT'
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OPERATORS = ['=',
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'!=',
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'>',
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'>=',
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'<',
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'<=',
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'begins with',
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'contains'
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]
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def defineCharacteristics(self):
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self.name = 'Extract by attribute'
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self.group = 'Vector selection tools'
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self.addParameter(ParameterVector(
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self.INPUT, 'Input Layer', [ParameterVector.VECTOR_TYPE_ANY]))
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self.addParameter(ParameterTableField(
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self.FIELD, 'Selection attribute', self.INPUT))
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self.addParameter(ParameterSelection(
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self.OPERATOR, 'Operator', self.OPERATORS))
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self.addParameter(ParameterString(self.VALUE, 'Value'))
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self.addOutput(OutputVector(self.OUTPUT, 'Output'))
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def processAlgorithm(self, progress):
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT))
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fieldName = self.getParameterValue(self.FIELD)
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operator = self.OPERATORS[self.getParameterValue(self.OPERATOR)]
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value = self.getParameterValue(self.VALUE)
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fields = layer.pendingFields()
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields,
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layer.wkbType(), layer.crs())
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idx = layer.fieldNameIndex(fieldName)
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fieldType = fields[idx].type()
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if fieldType != QVariant.String and operator in self.OPERATORS[-2:]:
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op = ''.join(['"%s", ' % o for o in self.OPERATORS[-2:]])
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raise GeoAlgorithmExecutionException(
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'Operators %s can be used only with string fields.' % op)
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if fieldType in [QVariant.Int, QVariant.Double]:
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progress.setInfo('Numeric field')
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expr = '"%s" %s %s' % (fieldName, operator, value)
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progress.setInfo(expr)
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elif fieldType == QVariant.String:
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progress.setInfo('String field')
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if operator not in self.OPERATORS[-2:]:
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expr = """"%s" %s '%s'""" % (fieldName, operator, value)
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elif operator == 'begins with':
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expr = """"%s" LIKE '%s%%'""" % (fieldName, value)
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elif operator == 'contains':
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expr = """"%s" LIKE '%%%s%%'""" % (fieldName, value)
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progress.setInfo(expr)
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elif fieldType in [QVariant.Date, QVariant.DateTime]:
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progress.setInfo('Date field')
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expr = """"%s" %s '%s'""" % (fieldX, operator, value)
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progress.setInfo(expr)
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else:
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raise GeoAlgorithmExecutionException(
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'Unsupported field type "%s"' % fields[idx].typeName())
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expression = QgsExpression(expr)
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expression.prepare(fields)
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features = vector.features(layer)
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count = len(features)
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total = 100.0 / float(count)
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for count, f in enumerate(features):
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if expression.evaluate(f, fields):
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writer.addFeature(f)
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progress.setPercentage(int(count * total))
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del writer
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