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119 lines
4.8 KiB
Python
119 lines
4.8 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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FieldsCalculator.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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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.parameters.ParameterVector import ParameterVector
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from processing.parameters.ParameterString import ParameterString
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from processing.parameters.ParameterNumber import ParameterNumber
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from processing.parameters.ParameterSelection import ParameterSelection
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from processing.outputs.OutputVector import OutputVector
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from processing.tools import dataobjects, vector
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class FieldsCalculator(GeoAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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FIELD_NAME = 'FIELD_NAME'
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FIELD_TYPE = 'FIELD_TYPE'
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FIELD_LENGTH = 'FIELD_LENGTH'
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FIELD_PRECISION = 'FIELD_PRECISION'
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FORMULA = 'FORMULA'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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TYPE_NAMES = ['Float', 'Integer', 'String']
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TYPES = [QVariant.Double, QVariant.Int, QVariant.String]
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def defineCharacteristics(self):
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self.name = 'Field calculator'
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self.group = 'Vector table tools'
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self.addParameter(ParameterVector(self.INPUT_LAYER, 'Input layer',
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[ParameterVector.VECTOR_TYPE_ANY], False))
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self.addParameter(ParameterString(self.FIELD_NAME, 'Result field name'
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))
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self.addParameter(ParameterSelection(self.FIELD_TYPE, 'Field type',
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self.TYPE_NAMES))
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self.addParameter(ParameterNumber(self.FIELD_LENGTH, 'Field length',
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1, 255, 10))
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self.addParameter(ParameterNumber(self.FIELD_PRECISION,
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'Field precision', 0, 10, 5))
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self.addParameter(ParameterString(self.FORMULA, 'Formula'))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, 'Output layer'))
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def processAlgorithm(self, progress):
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fieldName = self.getParameterValue(self.FIELD_NAME)
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fieldType = self.getParameterValue(self.FIELD_TYPE)
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fieldLength = self.getParameterValue(self.FIELD_LENGTH)
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fieldPrecision = self.getParameterValue(self.FIELD_PRECISION)
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formula = self.getParameterValue(self.FORMULA)
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output = self.getOutputFromName(self.OUTPUT_LAYER)
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT_LAYER))
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provider = layer.dataProvider()
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fields = provider.fields()
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fields.append(QgsField(fieldName, self.TYPES[fieldType], '',
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fieldLength, fieldPrecision))
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writer = output.getVectorWriter(fields, provider.geometryType(),
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layer.crs())
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outFeat = QgsFeature()
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inGeom = QgsGeometry()
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nFeat = provider.featureCount()
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nElement = 0
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features = vector.features(layer)
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fieldnames = [field.name() for field in provider.fields()]
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fieldnames.sort(key=len, reverse=False)
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fieldidx = [fieldnames.index(field.name()) for field in
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provider.fields()]
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print fieldidx
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for inFeat in features:
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progress.setPercentage(int(100 * nElement / nFeat))
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attrs = inFeat.attributes()
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expression = formula
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for idx in fieldidx:
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expression = expression.replace(unicode(fields[idx].name()),
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unicode(attrs[idx]))
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try:
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result = eval(expression)
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except Exception:
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result = None
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nElement += 1
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inGeom = inFeat.geometry()
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outFeat.setGeometry(inGeom)
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attrs = inFeat.attributes()
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attrs.append(result)
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outFeat.setAttributes(attrs)
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writer.addFeature(outFeat)
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del writer
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def checkParameterValuesBeforeExecuting(self):
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# TODO check that formula is correct and fields exist
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pass
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