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161 lines
7.1 KiB
Python
161 lines
7.1 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 qgis.PyQt.QtCore import QVariant
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from qgis.core import (QgsExpression,
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QgsExpressionContext,
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QgsExpressionContextUtils,
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QgsFeatureSink,
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QgsField,
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QgsDistanceArea,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterEnum,
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QgsProcessingParameterNumber,
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QgsProcessingParameterBoolean,
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QgsProcessingParameterExpression,
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QgsProcessingParameterString,
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QgsProcessingParameterFeatureSink,
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QgsProcessingException)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from .ui.FieldsCalculatorDialog import FieldsCalculatorDialog
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class FieldsCalculator(QgisAlgorithm):
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INPUT = 'INPUT'
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NEW_FIELD = 'NEW_FIELD'
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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 = 'OUTPUT'
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TYPES = [QVariant.Double, QVariant.Int, QVariant.String, QVariant.Date]
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def group(self):
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return self.tr('Vector table')
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def __init__(self):
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super().__init__()
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self.type_names = [self.tr('Float'),
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self.tr('Integer'),
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self.tr('String'),
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self.tr('Date')]
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def initAlgorithm(self, config=None):
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self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT, self.tr('Input layer')))
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self.addParameter(QgsProcessingParameterString(self.FIELD_NAME,
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self.tr('Result field name')))
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self.addParameter(QgsProcessingParameterEnum(self.FIELD_TYPE,
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self.tr('Field type'), options=self.type_names))
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self.addParameter(QgsProcessingParameterNumber(self.FIELD_LENGTH,
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self.tr('Field length'), minValue=1, maxValue=255, defaultValue=10))
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self.addParameter(QgsProcessingParameterNumber(self.FIELD_PRECISION,
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self.tr('Field precision'), minValue=0, maxValue=15, defaultValue=3))
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self.addParameter(QgsProcessingParameterBoolean(self.NEW_FIELD,
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self.tr('Create new field'), defaultValue=True))
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self.addParameter(QgsProcessingParameterExpression(self.FORMULA, self.tr('Formula')))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
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self.tr('Calculated')))
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def name(self):
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return 'fieldcalculator'
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def displayName(self):
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return self.tr('Field calculator')
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def processAlgorithm(self, parameters, context, feedback):
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source = self.parameterAsSource(parameters, self.INPUT, context)
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layer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
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field_name = self.parameterAsString(parameters, self.FIELD_NAME, context)
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field_type = self.TYPES[self.parameterAsEnum(parameters, self.FIELD_TYPE, context)]
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width = self.parameterAsInt(parameters, self.FIELD_LENGTH, context)
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precision = self.parameterAsInt(parameters, self.FIELD_PRECISION, context)
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new_field = self.parameterAsBool(parameters, self.NEW_FIELD, context)
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formula = self.parameterAsString(parameters, self.FORMULA, context)
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expression = QgsExpression(formula)
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da = QgsDistanceArea()
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da.setSourceCrs(source.sourceCrs())
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da.setEllipsoid(context.project().ellipsoid())
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expression.setGeomCalculator(da)
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expression.setDistanceUnits(context.project().distanceUnits())
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expression.setAreaUnits(context.project().areaUnits())
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fields = source.fields()
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field_index = fields.lookupField(field_name)
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if new_field or field_index < 0:
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fields.append(QgsField(field_name, field_type, '', width, precision))
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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fields, source.wkbType(), source.sourceCrs())
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exp_context = self.createExpressionContext(parameters, context)
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if layer is not None:
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exp_context.appendScope(QgsExpressionContextUtils.layerScope(layer))
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if not expression.prepare(exp_context):
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raise QgsProcessingException(
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self.tr('Evaluation error: {0}').format(expression.parserErrorString()))
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features = source.getFeatures()
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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for current, f in enumerate(features):
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if feedback.isCanceled():
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break
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rownum = current + 1
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exp_context.setFeature(f)
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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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feedback.reportError(expression.evalErrorString())
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else:
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attrs = f.attributes()
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if new_field or field_index < 0:
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attrs.append(value)
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else:
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attrs[field_index] = value
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f.setAttributes(attrs)
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sink.addFeature(f, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(current * total))
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return {self.OUTPUT: dest_id}
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def checkParameterValues(self, parameters, context):
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newField = self.parameterAsBool(parameters, self.NEW_FIELD, context)
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fieldName = self.parameterAsString(parameters, self.FIELD_NAME, context).strip()
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if newField and len(fieldName) == 0:
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return False, self.tr('Field name is not set. Please enter a field name')
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return super(FieldsCalculator, self).checkParameterValues(parameters, context)
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def createCustomParametersWidget(self, parent):
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return FieldsCalculatorDialog(self)
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