QGIS/python/plugins/processing/algs/qgis/FieldsCalculator.py
Victor Olaya 293ac60722 [processing] removed interface module
now all access to the interface is done through qgis.utils.iface
2014-05-21 17:35:48 +02:00

164 lines
6.6 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
FieldsCalculator.py
---------------------
Date : August 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from PyQt4.QtCore import *
from qgis.core import *
from qgis.utils import iface
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import \
GeoAlgorithmExecutionException
from processing.parameters.ParameterVector import ParameterVector
from processing.parameters.ParameterString import ParameterString
from processing.parameters.ParameterNumber import ParameterNumber
from processing.parameters.ParameterBoolean import ParameterBoolean
from processing.parameters.ParameterSelection import ParameterSelection
from processing.outputs.OutputVector import OutputVector
from processing.tools import dataobjects, vector, system
from ui.FieldsCalculatorDialog import FieldsCalculatorDialog
class FieldsCalculator(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
NEW_FIELD = 'NEW_FIELD'
FIELD_NAME = 'FIELD_NAME'
FIELD_TYPE = 'FIELD_TYPE'
FIELD_LENGTH = 'FIELD_LENGTH'
FIELD_PRECISION = 'FIELD_PRECISION'
FORMULA = 'FORMULA'
OUTPUT_LAYER = 'OUTPUT_LAYER'
TYPE_NAMES = ['Float', 'Integer', 'String', 'Date']
TYPES = [QVariant.Double, QVariant.Int, QVariant.String, QVariant.Date]
def defineCharacteristics(self):
self.name = 'Field calculator'
self.group = 'Vector table tools'
self.addParameter(ParameterVector(self.INPUT_LAYER, 'Input layer',
[ParameterVector.VECTOR_TYPE_ANY], False))
self.addParameter(ParameterString(self.FIELD_NAME, 'Result field name'
))
self.addParameter(ParameterSelection(self.FIELD_TYPE, 'Field type',
self.TYPE_NAMES))
self.addParameter(ParameterNumber(self.FIELD_LENGTH, 'Field length',
1, 255, 10))
self.addParameter(ParameterNumber(self.FIELD_PRECISION,
'Field precision', 0, 15, 3))
self.addParameter(ParameterBoolean(self.NEW_FIELD,
'Create new field', True))
self.addParameter(ParameterString(self.FORMULA, 'Formula'))
self.addOutput(OutputVector(self.OUTPUT_LAYER, 'Output layer'))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_LAYER))
fieldName = self.getParameterValue(self.FIELD_NAME)
fieldType = self.TYPES[self.getParameterValue(self.FIELD_TYPE)]
width = self.getParameterValue(self.FIELD_LENGTH)
precision = self.getParameterValue(self.FIELD_PRECISION)
newField = self.getParameterValue(self.NEW_FIELD)
formula = self.getParameterValue(self.FORMULA)
output = self.getOutputFromName(self.OUTPUT_LAYER)
if output.value == '':
ext = output.getDefaultFileExtension(self)
output.value = system.getTempFilenameInTempFolder(output.name + '.' + ext)
provider = layer.dataProvider()
fields = layer.pendingFields()
if newField:
fields.append(QgsField(fieldName, fieldType, '', width, precision))
writer = output.getVectorWriter(fields, provider.geometryType(),
layer.crs())
exp = QgsExpression(formula)
da = QgsDistanceArea()
da.setSourceCrs(layer.crs().srsid())
canvas = iface.mapCanvas()
da.setEllipsoidalMode(canvas.mapRenderer().hasCrsTransformEnabled())
da.setEllipsoid(QgsProject.instance().readEntry('Measure',
'/Ellipsoid',
GEO_NONE)[0])
exp.setGeomCalculator(da)
if not exp.prepare(layer.pendingFields()):
raise GeoAlgorithmExecutionException(
'Evaluation error: ' + exp.evalErrorString())
outFeature = QgsFeature()
outFeature.initAttributes(len(fields))
outFeature.setFields(fields)
error = ''
calculationSuccess = True
current = 0
features = vector.features(layer)
total = 100.0 / len(features)
rownum = 1
for current, f in enumerate(features):
rownum = current + 1
exp.setCurrentRowNumber(rownum)
value = exp.evaluate(f)
if exp.hasEvalError():
calculationSuccess = False
error = exp.evalErrorString()
break
else:
outFeature.setGeometry(f.geometry())
for fld in f.fields():
outFeature[fld.name()] = f[fld.name()]
outFeature[fieldName] = value
writer.addFeature(outFeature)
progress.setPercentage(int(current * total))
del writer
if not calculationSuccess:
raise GeoAlgorithmExecutionException(
'An error occured while evaluating the calculation '
'string:\n' + error)
def checkParameterValuesBeforeExecuting(self):
newField = self.getParameterValue(self.NEW_FIELD)
fieldName = self.getParameterValue(self.FIELD_NAME)
if newField and len(fieldName) == 0:
raise GeoAlgorithmExecutionException('Field name is not set. '
'Please enter a field name')
outputName = self.getOutputValue(self.OUTPUT_LAYER)
if outputName == '':
raise GeoAlgorithmExecutionException('Output is not set. '
'Please specify valid filename')
def getCustomParametersDialog(self):
return FieldsCalculatorDialog(self)