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06c4b07222
Since the layer has more complete knowledge of the crs (ie, when provider could not determine crs and user has selected it from the list), and also better knowledge of layer fields (virtual fields, joined fields) we should use these rather than the provider methods.
158 lines
6.4 KiB
Python
158 lines
6.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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FieldsMapper.py
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---------------------
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Date : October 2014
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Copyright : (C) 2014 by Arnaud Morvan
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Email : arnaud dot morvan at camptocamp 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__ = 'Arnaud Morvan'
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__date__ = 'October 2014'
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__copyright__ = '(C) 2014, Arnaud Morvan'
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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 qgis.core import QgsField, QgsExpression, QgsExpressionContext, QgsExpressionContextUtils, QgsDistanceArea, QgsProject, QgsFeature, GEO_NONE
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from qgis.utils import iface
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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.parameters import ParameterTable
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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from .fieldsmapping import ParameterFieldsMapping
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from .ui.FieldsMapperDialogs import (FieldsMapperParametersDialog,
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FieldsMapperModelerParametersDialog)
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class FieldsMapper(GeoAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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FIELDS_MAPPING = 'FIELDS_MAPPING'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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def __init__(self):
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GeoAlgorithm.__init__(self)
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self.mapping = None
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Refactor fields')
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self.group, self.i18n_group = self.trAlgorithm('Vector table tools')
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self.addParameter(ParameterTable(self.INPUT_LAYER,
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self.tr('Input layer'),
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False))
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self.addParameter(ParameterFieldsMapping(self.FIELDS_MAPPING,
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self.tr('Fields mapping'),
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self.INPUT_LAYER))
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self.addOutput(OutputVector(self.OUTPUT_LAYER,
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self.tr('Refactored'),
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base_input=self.INPUT_LAYER))
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def processAlgorithm(self, progress):
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layer = self.getParameterValue(self.INPUT_LAYER)
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mapping = self.getParameterValue(self.FIELDS_MAPPING)
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output = self.getOutputFromName(self.OUTPUT_LAYER)
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layer = dataobjects.getObjectFromUri(layer)
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fields = []
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expressions = []
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da = QgsDistanceArea()
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da.setSourceCrs(layer.crs().srsid())
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da.setEllipsoidalMode(
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iface.mapCanvas().mapSettings().hasCrsTransformEnabled())
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da.setEllipsoid(QgsProject.instance().readEntry(
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'Measure', '/Ellipsoid', GEO_NONE)[0])
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exp_context = QgsExpressionContext()
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exp_context.appendScope(QgsExpressionContextUtils.globalScope())
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exp_context.appendScope(QgsExpressionContextUtils.projectScope())
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exp_context.appendScope(QgsExpressionContextUtils.layerScope(layer))
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for field_def in mapping:
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fields.append(QgsField(name=field_def['name'],
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type=field_def['type'],
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len=field_def['length'],
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prec=field_def['precision']))
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expression = QgsExpression(field_def['expression'])
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expression.setGeomCalculator(da)
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expression.setDistanceUnits(QgsProject.instance().distanceUnits())
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expression.setAreaUnits(QgsProject.instance().areaUnits())
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if expression.hasParserError():
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raise GeoAlgorithmExecutionException(
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self.tr(u'Parser error in expression "{}": {}')
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.format(unicode(field_def['expression']),
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unicode(expression.parserErrorString())))
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expression.prepare(exp_context)
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if expression.hasEvalError():
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raise GeoAlgorithmExecutionException(
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self.tr(u'Evaluation error in expression "{}": {}')
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.format(unicode(field_def['expression']),
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unicode(expression.evalErrorString())))
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expressions.append(expression)
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writer = output.getVectorWriter(fields,
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layer.wkbType(),
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layer.crs())
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# Create output vector layer with new attributes
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error = ''
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calculationSuccess = True
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inFeat = QgsFeature()
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outFeat = QgsFeature()
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features = vector.features(layer)
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total = 100.0 / len(features)
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for current, inFeat in enumerate(features):
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rownum = current + 1
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geometry = inFeat.geometry()
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outFeat.setGeometry(geometry)
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attrs = []
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for i in xrange(0, len(mapping)):
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field_def = mapping[i]
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expression = expressions[i]
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exp_context.setFeature(inFeat)
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exp_context.lastScope().setVariable("row_number", rownum)
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value = expression.evaluate(exp_context)
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if expression.hasEvalError():
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calculationSuccess = False
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error = expression.evalErrorString()
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break
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attrs.append(value)
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outFeat.setAttributes(attrs)
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writer.addFeature(outFeat)
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progress.setPercentage(int(current * total))
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del writer
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if not calculationSuccess:
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raise GeoAlgorithmExecutionException(
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self.tr('An error occurred while evaluating the calculation'
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' string:\n') + error)
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def getCustomParametersDialog(self):
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return FieldsMapperParametersDialog(self)
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def getCustomModelerParametersDialog(self, modelAlg, algName=None):
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return FieldsMapperModelerParametersDialog(self, modelAlg, algName)
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