QGIS/python/plugins/processing/algs/qgis/FieldPyculator.py

182 lines
7.0 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
FieldPyculator.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 & NextGIS'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya & NextGIS'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import sys
from PyQt4.QtCore import *
from qgis.core import *
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.ParameterSelection import ParameterSelection
from processing.outputs.OutputVector import OutputVector
from processing.tools import dataobjects, vector
class FieldsPyculator(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
FIELD_NAME = 'FIELD_NAME'
FIELD_TYPE = 'FIELD_TYPE'
FIELD_LENGTH = 'FIELD_LENGTH'
FIELD_PRECISION = 'FIELD_PRECISION'
GLOBAL = 'GLOBAL'
FORMULA = 'FORMULA'
OUTPUT_LAYER = 'OUTPUT_LAYER'
RESULT_VAR_NAME = 'value'
TYPE_NAMES = ['Integer', 'Float', 'String']
TYPES = [QVariant.Int, QVariant.Double, QVariant.String]
def defineCharacteristics(self):
self.name = 'Advanced Python 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'
, 'NewField'))
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, 10, 0))
self.addParameter(ParameterString(self.GLOBAL, 'Global expression',
multiline=True, optional=True))
self.addParameter(ParameterString(self.FORMULA, 'Formula', 'value = ',
multiline=True))
self.addOutput(OutputVector(self.OUTPUT_LAYER, 'Output layer'))
def processAlgorithm(self, progress):
fieldName = self.getParameterValue(self.FIELD_NAME)
fieldType = self.getParameterValue(self.FIELD_TYPE)
fieldLength = self.getParameterValue(self.FIELD_LENGTH)
fieldPrecision = self.getParameterValue(self.FIELD_PRECISION)
code = self.getParameterValue(self.FORMULA)
globalExpression = self.getParameterValue(self.GLOBAL)
output = self.getOutputFromName(self.OUTPUT_LAYER)
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_LAYER))
provider = layer.dataProvider()
fields = provider.fields()
fields.append(QgsField(fieldName, self.TYPES[fieldType], '',
fieldLength, fieldPrecision))
writer = output.getVectorWriter(fields, provider.geometryType(),
layer.crs())
outFeat = QgsFeature()
new_ns = {}
# Run global code
if globalExpression.strip() != '':
try:
bytecode = compile(globalExpression, '<string>', 'exec')
exec bytecode in new_ns
except:
raise GeoAlgorithmExecutionException(
'FieldPyculator code execute error\n'
+ "Global code block can't be executed!%s \n %s"
% (unicode(sys.exc_info()[0].__name__),
unicode(sys.exc_info()[1])))
# Replace all fields tags
fields = provider.fields()
num = 0
for field in fields:
field_name = unicode(field.name())
replval = '__attr[' + str(num) + ']'
code = code.replace('<' + field_name + '>', replval)
num += 1
# Replace all special vars
code = code.replace('$id', '__id')
code = code.replace('$geom', '__geom')
need_id = code.find('__id') != -1
need_geom = code.find('__geom') != -1
need_attrs = code.find('__attr') != -1
# Compile
try:
bytecode = compile(code, '<string>', 'exec')
except:
raise GeoAlgorithmExecutionException(
'FieldPyculator code execute error\n'
+ "Field code block can't be executed! %s \n %s",
unicode(sys.exc_info()[0].__name__),
unicode(sys.exc_info()[1]))
# Run
features = vector.features(layer)
nFeatures = len(features)
nElement = 1
for feat in features:
progress.setPercentage(int(100 * nElement / nFeatures))
attrs = feat.attributes()
feat_id = feat.id()
# Add needed vars
if need_id:
new_ns['__id'] = feat_id
if need_geom:
geom = feat.geometry()
new_ns['__geom'] = geom
if need_attrs:
pyattrs = [a for a in attrs]
new_ns['__attr'] = pyattrs
# Clear old result
if self.RESULT_VAR_NAME in new_ns:
del new_ns[self.RESULT_VAR_NAME]
# Exec
exec bytecode in new_ns
# Check result
if self.RESULT_VAR_NAME not in new_ns:
raise GeoAlgorithmExecutionException(
'FieldPyculator code execute error\n'
+ "Field code block does not return '%s1' variable! \
Please declare this variable in your code!"
% self.RESULT_VAR_NAME)
# Write feature
nElement += 1
outFeat.setGeometry(feat.geometry())
attrs.append(new_ns[self.RESULT_VAR_NAME])
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
del writer
def checkParameterValuesBeforeExecuting(self):
# TODO check that formula is correct and fields exist
pass