QGIS/python/plugins/sextante/ftools/PolygonsToLines.py
2012-09-15 18:30:32 +03:00

69 lines
2.5 KiB
Python

from sextante.core.GeoAlgorithm import GeoAlgorithm
import os.path
from PyQt4 import QtGui
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.core import *
from sextante.parameters.ParameterVector import ParameterVector
from sextante.core.QGisLayers import QGisLayers
from sextante.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from sextante.outputs.OutputVector import OutputVector
class PolygonsToLines(GeoAlgorithm):
INPUT = "INPUT"
OUTPUT = "OUTPUT"
def getIcon(self):
return QtGui.QIcon(os.path.dirname(__file__) + "/icons/to_lines.png")
def processAlgorithm(self, progress):
vlayer = QGisLayers.getObjectFromUri(self.getParameterValue(PolygonsToLines.INPUT))
vprovider = vlayer.dataProvider()
allAttrs = vprovider.attributeIndexes()
vprovider.select( allAttrs )
fields = vprovider.fields()
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QGis.WKBLineString, vprovider.crs() )
inFeat = QgsFeature()
outFeat = QgsFeature()
inGeom = QgsGeometry()
outGeom = QgsGeometry()
nFeat = vprovider.featureCount()
nElement = 0
while vprovider.nextFeature(inFeat):
multi = False
nElement += 1
progress.setPercentage(int(nElement/nFeat * 100))
inGeom = inFeat.geometry()
if inGeom.isMultipart():
multi = True
atMap = inFeat.attributeMap()
lineList = self.extractAsLine( inGeom )
outFeat.setAttributeMap( atMap )
for h in lineList:
outFeat.setGeometry( outGeom.fromPolyline( h ) )
writer.addFeature( outFeat )
del writer
def extractAsLine( self, geom ):
multi_geom = QgsGeometry()
temp_geom = []
if geom.type() == 2:
if geom.isMultipart():
multi_geom = geom.asMultiPolygon()
for i in multi_geom:
temp_geom.extend(i)
else:
multi_geom = geom.asPolygon()
temp_geom = multi_geom
return temp_geom
else:
return []
def defineCharacteristics(self):
self.name = "Polygons to lines"
self.group = "Geometry tools"
self.addParameter(ParameterVector(PolygonsToLines.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_POLYGON))
self.addOutput(OutputVector(PolygonsToLines.OUTPUT, "Output layer"))
#=========================================================