mirror of
https://github.com/qgis/QGIS.git
synced 2025-03-08 00:02:35 -05:00
aca22663d0
Since it's much more useful. Also add a prompt for layer name, so that you can save the results of an algorithm into an existing geopackage without wiping existing layers.
119 lines
4.7 KiB
Python
Executable File
119 lines
4.7 KiB
Python
Executable File
# -*- coding: utf-8 -*-
|
|
|
|
"""
|
|
***************************************************************************
|
|
GeometryByExpression.py
|
|
-----------------------
|
|
Date : October 2016
|
|
Copyright : (C) 2016 by Nyall Dawson
|
|
Email : nyall dot dawson 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__ = 'Nyall Dawson'
|
|
__date__ = 'October 2016'
|
|
__copyright__ = '(C) 2016, Nyall Dawson'
|
|
|
|
# This will get replaced with a git SHA1 when you do a git archive323
|
|
|
|
__revision__ = '$Format:%H$'
|
|
|
|
from qgis.core import (QgsWkbTypes,
|
|
QgsExpression,
|
|
QgsGeometry,
|
|
QgsProcessingException,
|
|
QgsProcessingParameterBoolean,
|
|
QgsProcessingParameterEnum,
|
|
QgsProcessingParameterExpression)
|
|
|
|
from processing.algs.qgis.QgisAlgorithm import QgisFeatureBasedAlgorithm
|
|
|
|
|
|
class GeometryByExpression(QgisFeatureBasedAlgorithm):
|
|
|
|
OUTPUT_GEOMETRY = 'OUTPUT_GEOMETRY'
|
|
WITH_Z = 'WITH_Z'
|
|
WITH_M = 'WITH_M'
|
|
EXPRESSION = 'EXPRESSION'
|
|
|
|
def group(self):
|
|
return self.tr('Vector geometry')
|
|
|
|
def __init__(self):
|
|
super().__init__()
|
|
self.geometry_types = [self.tr('Polygon'),
|
|
'Line',
|
|
'Point']
|
|
|
|
def initParameters(self, config=None):
|
|
self.addParameter(QgsProcessingParameterEnum(
|
|
self.OUTPUT_GEOMETRY,
|
|
self.tr('Output geometry type'),
|
|
options=self.geometry_types, defaultValue=0))
|
|
self.addParameter(QgsProcessingParameterBoolean(self.WITH_Z,
|
|
self.tr('Output geometry has z dimension'), defaultValue=False))
|
|
self.addParameter(QgsProcessingParameterBoolean(self.WITH_M,
|
|
self.tr('Output geometry has m values'), defaultValue=False))
|
|
|
|
self.addParameter(QgsProcessingParameterExpression(self.EXPRESSION,
|
|
self.tr("Geometry expression"), defaultValue='$geometry', parentLayerParameterName='INPUT'))
|
|
|
|
def name(self):
|
|
return 'geometrybyexpression'
|
|
|
|
def displayName(self):
|
|
return self.tr('Geometry by expression')
|
|
|
|
def outputName(self):
|
|
return self.tr('Modified geometry')
|
|
|
|
def prepareAlgorithm(self, parameters, context, feedback):
|
|
self.geometry_type = self.parameterAsEnum(parameters, self.OUTPUT_GEOMETRY, context)
|
|
self.wkb_type = None
|
|
if self.geometry_type == 0:
|
|
self.wkb_type = QgsWkbTypes.Polygon
|
|
elif self.geometry_type == 1:
|
|
self.wkb_type = QgsWkbTypes.LineString
|
|
else:
|
|
self.wkb_type = QgsWkbTypes.Point
|
|
if self.parameterAsBool(parameters, self.WITH_Z, context):
|
|
self.wkb_type = QgsWkbTypes.addZ(self.wkb_type)
|
|
if self.parameterAsBool(parameters, self.WITH_M, context):
|
|
self.wkb_type = QgsWkbTypes.addM(self.wkb_type)
|
|
|
|
self.expression = QgsExpression(self.parameterAsString(parameters, self.EXPRESSION, context))
|
|
if self.expression.hasParserError():
|
|
feedback.reportError(self.expression.parserErrorString())
|
|
return False
|
|
|
|
self.expression_context = self.createExpressionContext(parameters, context)
|
|
self.expression.prepare(self.expression_context)
|
|
|
|
return True
|
|
|
|
def outputWkbType(self, input_wkb_type):
|
|
return self.wkb_type
|
|
|
|
def processFeature(self, feature, feedback):
|
|
self.expression_context.setFeature(feature)
|
|
value = self.expression.evaluate(self.expression_context)
|
|
if self.expression.hasEvalError():
|
|
raise QgsProcessingException(
|
|
self.tr('Evaluation error: {0}').format(self.expression.evalErrorString()))
|
|
|
|
if not value:
|
|
feature.setGeometry(QgsGeometry())
|
|
else:
|
|
if not isinstance(value, QgsGeometry):
|
|
raise QgsProcessingException(
|
|
self.tr('{} is not a geometry').format(value))
|
|
feature.setGeometry(value)
|
|
return feature
|