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Commit e527fe3

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volayavolaya
committedSep 21, 2013
Added "eliminate sliver polygons" algorithm skeleton(still a draft first version)
·
ltr-3_40archive/master_2
1 parent 8a48b9f commit e527fe3

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‎python/plugins/processing/algs/QGISAlgorithmProvider.py

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***************************************************************************
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"""
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from processing.algs.Polygonize import Polygonize
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from processing.algs.ftools.Eliminate import Eliminate
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__author__ = 'Victor Olaya'
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__date__ = 'December 2012'
@@ -112,7 +113,7 @@ def __init__(self):
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ExportGeometryInfo(), Centroids(), Delaunay(), VoronoiPolygons(),
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SimplifyGeometries(), DensifyGeometries(), DensifyGeometriesInterval(),
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MultipartToSingleparts(), SinglePartsToMultiparts(), PolygonsToLines(),
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LinesToPolygons(), ExtractNodes(),
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LinesToPolygons(), ExtractNodes(),Eliminate(),
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# geoprocessing
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ConvexHull(), FixedDistanceBuffer(), VariableDistanceBuffer(),
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Dissolve(), Difference(), Intersection(), Union(), Clip(),

‎python/plugins/processing/algs/ftools/Eliminate.py

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# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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Eliminate.py
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---------------------
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Date : August 2012
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Copyright : (C) 2013 by Bernhard Str�bl
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Email : bernhard.stroebl@jena.de
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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from processing.parameters.ParameterSelection import ParameterSelection
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from PyQt4 import QtCore
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__author__ = 'Bernhard Strobl'
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__date__ = 'August 2013'
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__copyright__ = '(C) 2013, Bernhard Strobl'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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from PyQt4.QtCore import *
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from qgis.core import *
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.tools import dataobjects
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from processing.parameters.ParameterVector import ParameterVector
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from processing.outputs.OutputVector import OutputVector
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class Eliminate(GeoAlgorithm):
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INPUT = "INPUT"
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OUTPUT = "OUTPUT"
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MODE = "MODE"
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MODES = ["Area", "Common boundary"]
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MODE_AREA = 0
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MODE_BOUNDARY = 1
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def defineCharacteristics(self):
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self.name = "Eliminate sliver polygons"
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self.group = "Vector geometry tools"
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self.addParameter(ParameterVector(self.INPUT, "Input layer", [ParameterVector.VECTOR_TYPE_POLYGON]))
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self.addParameter(ParameterSelection(self.MODE, "Segments", self.MODES))
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self.addOutput(OutputVector(self.OUTPUT, "Cleaned layer"))
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def processAlgorithm(self, progress):
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inLayer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
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boundary = self.getParameterValue(self.MODE) == self.MODE_BOUNDARY
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# keep references to the features to eliminate
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fidsToEliminate = inLayer.selectedFeaturesIds()
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provider = inLayer.dataProvider()
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output = self.getOutputFromName(self.OUTPUT)
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writer = output.getVectorWriter( provider.fields(),
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provider.geometryType(),
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inLayer.crs() )
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#write all features to output layer
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iterator = inLayer.getFeatures()
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for feature in iterator:
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writer.addFeature(feature)
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#Open the layer to start cleaning it
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outFileName = output.value
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outLayer = QgsVectorLayer(outFileName, QtCore.QFileInfo(outFileName).completeBaseName(), "ogr")
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# delete features to be eliminated in outLayer
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outLayer.setSelectedFeatures(fidsToEliminate)
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outLayer.startEditing()
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if outLayer.deleteSelectedFeatures():
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if self.saveChanges(outLayer):
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outLayer.startEditing()
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else:
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raise GeoAlgorithmExecutionException("Could not delete features")
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# ANALYZE
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start = 20.00
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progress.setPercentage(start)
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add = 80.00 / len(fidsToEliminate)
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lastLen = 0
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geomsToMerge = dict()
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# we go through the list and see if we find any polygons we can merge the selected with
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# if we have no success with some we merge and then restart the whole story
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while (lastLen != inLayer.selectedFeatureCount()): #check if we made any progress
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lastLen = inLayer.selectedFeatureCount()
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fidsToDeselect = []
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#iterate over the polygons to eliminate
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for fid2Eliminate in inLayer.selectedFeaturesIds():
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feat = QgsFeature()
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if inLayer.getFeatures( QgsFeatureRequest().setFilterFid( fid2Eliminate ).setSubsetOfAttributes([]) ).nextFeature( feat ):
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geom2Eliminate = feat.geometry()
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bbox = geom2Eliminate.boundingBox()
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fit = outLayer.getFeatures( QgsFeatureRequest().setFilterRect( bbox ) )
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mergeWithFid = None
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mergeWithGeom = None
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max = 0
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selFeat = QgsFeature()
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while fit.nextFeature(selFeat):
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selGeom = selFeat.geometry()
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if geom2Eliminate.intersects(selGeom): # we have a candidate
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iGeom = geom2Eliminate.intersection(selGeom)
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if boundary:
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selValue = iGeom.length()
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else:
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# we need a common boundary
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if 0 < iGeom.length():
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selValue = selGeom.area()
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else:
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selValue = 0
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if selValue > max:
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max = selValue
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mergeWithFid = selFeat.id()
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mergeWithGeom = QgsGeometry(selGeom) # deep copy of the geometry
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if mergeWithFid != None: # a successful candidate
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newGeom = mergeWithGeom.combine(geom2Eliminate)
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if outLayer.changeGeometry(mergeWithFid, newGeom):
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# write change back to disc
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if self.saveChanges(outLayer):
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outLayer.startEditing()
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else:
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return
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# mark feature as eliminated in inLayer
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fidsToDeselect.append(fid2Eliminate)
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else:
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raise GeoAlgorithmExecutionException("Could not replace geometry of feature with id %s" % (mergeWithFid))
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start = start + add
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progress.setPercentage(start)
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# end for fid2Eliminate
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# deselect features that are already eliminated in inLayer
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inLayer.deselect(fidsToDeselect)
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#end while
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if inLayer.selectedFeatureCount() > 0:
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# copy all features that could not be eliminated to outLayer
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if outLayer.addFeatures(inLayer.selectedFeatures()):
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# inform user
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fidList = ""
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for fid in inLayer.selectedFeaturesIds():
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if not fidList == "":
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fidList += ", "
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fidList += str(fid)
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raise GeoAlgorithmExecutionException("Could not eliminate features with these ids:\n%s" % (fidList))
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else:
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raise GeoAlgorithmExecutionException("Could not add features")
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# stop editing outLayer and commit any pending changes
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self.saveChanges(outLayer)
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def saveChanges(self, outLayer):
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if not outLayer.commitChanges():
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msg = ""
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for aStrm in outLayer.commitErrors():
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msg = msg + "\n" + aStrm
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outLayer.rollBack()
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raise GeoAlgorithmExecutionException("Commit error:\n%s" % (msg))

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