2012-10-04 19:36:43 +02:00

90 lines
3.1 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 archive
__revision__ = '$Format:%H$'
import os.path
from PyQt4 import QtGui
from PyQt4.QtCore import *
from qgis.core import *
from sextante.core.GeoAlgorithm import GeoAlgorithm
from sextante.core.QGisLayers import QGisLayers
from sextante.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from sextante.parameters.ParameterVector import ParameterVector
from sextante.outputs.OutputVector import OutputVector
class Centroids(GeoAlgorithm):
INPUT_LAYER = "INPUT_LAYER"
OUTPUT_LAYER = "OUTPUT_LAYER"
def getIcon(self):
return QtGui.QIcon(os.path.dirname(__file__) + "/icons/centroids.png")
def defineCharacteristics(self):
self.name = "Polygon centroids"
self.group = "Geometry tools"
self.addParameter(ParameterVector(self.INPUT_LAYER, "Input layer", ParameterVector.VECTOR_TYPE_POLYGON))
self.addOutput(OutputVector(self.OUTPUT_LAYER, "Output layer"))
def processAlgorithm(self, progress):
layer = QGisLayers.getObjectFromUri(self.getParameterValue(self.INPUT_LAYER))
outFileName = self.getOutputValue(self.OUTPUT_LAYER)
settings = QSettings()
encoding = settings.value( "/UI/encoding", "System" ).toString()
writer = self.getOutputFromName(self.OUTPUT_LAYER).getVectorWriter(layer.pendingFields(),
QGis.WKBPoint, layer.dataProvider().crs())
layer.select(layer.pendingAllAttributesList())
inFeat = QgsFeature()
outFeat = QgsFeature()
total = 100.0 / float(layer.featureCount())
current = 0
while layer.nextFeature(inFeat):
inGeom = inFeat.geometry()
attrMap = inFeat.attributeMap()
outGeom = QgsGeometry(inGeom.centroid())
if outGeom is None:
raise GeoAlgorithmExecutionException("Error calculating centroid")
outFeat.setGeometry(outGeom)
outFeat.setAttributeMap(attrMap)
writer.addFeature(outFeat)
current += 1
progress.setPercentage(int(current * total))
del writer