2015-08-22 14:29:41 +02:00

82 lines
2.9 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
Centroids.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 archive323
__revision__ = '$Format:%H$'
from qgis.core import QGis, QgsGeometry, QgsFeature
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
class Centroids(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Polygon centroids')
self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_POLYGON]))
self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Centroids')))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_LAYER))
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(
layer.pendingFields().toList(),
QGis.WKBPoint,
layer.crs())
outFeat = QgsFeature()
features = vector.features(layer)
total = 100.0 / float(len(features))
current = 0
for inFeat in features:
inGeom = inFeat.geometry()
attrs = inFeat.attributes()
outGeom = QgsGeometry(inGeom.centroid())
if outGeom is None:
raise GeoAlgorithmExecutionException(
self.tr('Error calculating centroid'))
outFeat.setGeometry(outGeom)
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
current += 1
progress.setPercentage(int(current * total))
del writer