QGIS/python/plugins/processing/algs/qgis/SinglePartsToMultiparts.py
nirvn 03e29d4f01 [processing] optimise singlepart to multipart algorithm
- keep z/m/curved geometries intact
- rewrite loop to avoid the cost of nb. feature x unique values
2016-11-03 09:05:31 +07:00

108 lines
3.7 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
SinglePartsToMultiparts.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. *
* *
***************************************************************************
"""
from builtins import str
__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__ = '$Format:%H$'
import os
from qgis.PyQt.QtGui import QIcon
from qgis.core import Qgis, QgsFeature, QgsGeometry, QgsWkbTypes
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTableField
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class SinglePartsToMultiparts(GeoAlgorithm):
INPUT = 'INPUT'
FIELD = 'FIELD'
OUTPUT = 'OUTPUT'
def getIcon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'single_to_multi.png'))
def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Singleparts to multipart')
self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
self.addParameter(ParameterVector(self.INPUT, self.tr('Input layer')))
self.addParameter(ParameterTableField(self.FIELD,
self.tr('Unique ID field'), self.INPUT))
self.addOutput(OutputVector(self.OUTPUT, self.tr('Multipart')))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
fieldName = self.getParameterValue(self.FIELD)
geomType = QgsWkbTypes.multiType(layer.wkbType())
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
layer.fields().toList(), geomType, layer.crs())
inFeat = QgsFeature()
outFeat = QgsFeature()
inGeom = QgsGeometry()
index = layer.fields().lookupField(fieldName)
collection_geom = {}
collection_attrs = {}
features = vector.features(layer)
current = 0
total = 100.0 / (len(features))
features = vector.features(layer)
for inFeat in features:
atMap = inFeat.attributes()
idVar = atMap[index]
key = str(idVar).strip()
if not key in collection_geom:
collection_geom[key] = []
collection_attrs[key] = atMap
inGeom = inFeat.geometry()
vType = inGeom.type()
collection_geom[key].append(inGeom)
current += 1
progress.setPercentage(int(current * total))
for key, geoms in collection_geom.items():
outFeat.setAttributes(collection_attrs[key])
outFeat.setGeometry(QgsGeometry.collectGeometry(geoms))
writer.addFeature(outFeat)
del writer