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e7fe61e6b9
available or compatible QGIS version is used Some housekeeping in QGIS algorithms provider
177 lines
7.2 KiB
Python
177 lines
7.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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FieldPyculator.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 & NextGIS'
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__date__ = 'August 2012'
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__copyright__ = '(C) 2012, Victor Olaya & NextGIS'
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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 sys
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from PyQt4.QtCore import QVariant
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from qgis.core import QgsFeature, QgsField
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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 ParameterVector
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from processing.core.parameters import ParameterString
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from processing.core.parameters import ParameterNumber
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from processing.core.parameters import ParameterSelection
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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 FieldsPyculator(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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GLOBAL = 'GLOBAL'
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FORMULA = 'FORMULA'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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RESULT_VAR_NAME = 'value'
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TYPES = [QVariant.Int, QVariant.Double, QVariant.String]
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Advanced Python field calculator')
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self.group, self.i18n_group = self.trAlgorithm('Vector table tools')
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self.type_names = [self.tr('Integer'),
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self.tr('Float'),
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self.tr('String')]
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self.addParameter(ParameterVector(self.INPUT_LAYER,
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self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_ANY], False))
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self.addParameter(ParameterString(self.FIELD_NAME,
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self.tr('Result field name'), 'NewField'))
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self.addParameter(ParameterSelection(self.FIELD_TYPE,
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self.tr('Field type'), self.type_names))
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self.addParameter(ParameterNumber(self.FIELD_LENGTH,
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self.tr('Field length'), 1, 255, 10))
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self.addParameter(ParameterNumber(self.FIELD_PRECISION,
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self.tr('Field precision'), 0, 10, 0))
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self.addParameter(ParameterString(self.GLOBAL,
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self.tr('Global expression'), multiline=True, optional=True))
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self.addParameter(ParameterString(self.FORMULA,
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self.tr('Formula'), 'value = ', multiline=True))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Calculated')))
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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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code = self.getParameterValue(self.FORMULA)
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globalExpression = self.getParameterValue(self.GLOBAL)
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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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new_ns = {}
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# Run global code
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if globalExpression.strip() != '':
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try:
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bytecode = compile(globalExpression, '<string>', 'exec')
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exec(bytecode, new_ns)
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except:
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raise GeoAlgorithmExecutionException(
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self.tr("FieldPyculator code execute error.Global code block can't be executed!\n%s\n%s" % (unicode(sys.exc_info()[0].__name__), unicode(sys.exc_info()[1]))))
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# Replace all fields tags
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fields = provider.fields()
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num = 0
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for field in fields:
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field_name = unicode(field.name())
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replval = '__attr[' + unicode(num) + ']'
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code = code.replace('<' + field_name + '>', replval)
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num += 1
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# Replace all special vars
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code = code.replace('$id', '__id')
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code = code.replace('$geom', '__geom')
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need_id = code.find('__id') != -1
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need_geom = code.find('__geom') != -1
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need_attrs = code.find('__attr') != -1
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# Compile
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try:
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bytecode = compile(code, '<string>', 'exec')
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except:
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raise GeoAlgorithmExecutionException(
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self.tr("FieldPyculator code execute error.Field code block can't be executed!\n%s\n%s" % (unicode(sys.exc_info()[0].__name__), unicode(sys.exc_info()[1]))))
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# Run
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features = vector.features(layer)
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total = 100.0 / len(features)
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for current, feat in enumerate(features):
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progress.setPercentage(int(current * total))
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attrs = feat.attributes()
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feat_id = feat.id()
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# Add needed vars
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if need_id:
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new_ns['__id'] = feat_id
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if need_geom:
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geom = feat.geometry()
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new_ns['__geom'] = geom
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if need_attrs:
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pyattrs = [a for a in attrs]
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new_ns['__attr'] = pyattrs
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# Clear old result
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if self.RESULT_VAR_NAME in new_ns:
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del new_ns[self.RESULT_VAR_NAME]
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# Exec
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exec(bytecode, new_ns)
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# Check result
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if self.RESULT_VAR_NAME not in new_ns:
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raise GeoAlgorithmExecutionException(
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self.tr("FieldPyculator code execute error\n"
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"Field code block does not return '%s1' variable! "
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"Please declare this variable in your code!" % self.RESULT_VAR_NAME))
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# Write feature
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outFeat.setGeometry(feat.geometry())
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attrs.append(new_ns[self.RESULT_VAR_NAME])
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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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