[sextante] added Polygonize algorithm by Piotr Pociask

qgis · Mar 28, 2013 · 1c0f6c6 · 1c0f6c6
1 parent da57be0
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diff --git a/python/plugins/sextante/algs/Polygonize.py b/python/plugins/sextante/algs/Polygonize.py
@@ -0,0 +1,95 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    Polygonize.py
+    ---------------------
+    Date                 : March 2013
+    Copyright            : (C) 2013 by Piotr Pociask
+    Email                : ppociask at o2 dot pl
+***************************************************************************
+*                                                                         *
+*   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__ = 'Piotr Pociask'
+__date__ = 'March 2013'
+__copyright__ = '(C) 2013, Piotr Pociask'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+from sextante.core.GeoAlgorithm import GeoAlgorithm
+from PyQt4.QtCore import QVariant
+from qgis.core import QgsFeature, QgsField, QgsFields, QgsGeometry, QGis
+from sextante.parameters.ParameterVector import ParameterVector
+from sextante.parameters.ParameterBoolean import ParameterBoolean
+from sextante.core.QGisLayers import QGisLayers
+from sextante.outputs.OutputVector import OutputVector
+from sextante.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
+
+class Polygonize(GeoAlgorithm):
+    INPUT = "INPUT"
+    OUTPUT = "OUTPUT"
+    FIELDS = "FIELDS"
+    GEOMETRY = "GEOMETRY"
+
+    def processAlgorithm(self, progress):
+        try:
+            from shapely.ops import polygonize
+            from shapely.geometry import Point,MultiLineString
+        except ImportError:
+            raise GeoAlgorithmExecutionException('Polygonize algorithm requires shapely module!')
+        vlayer = QGisLayers.getObjectFromUri(self.getParameterValue(self.INPUT))
+        output = self.getOutputFromName(self.OUTPUT)
+        vprovider = vlayer.dataProvider()
+        if self.getParameterValue(self.FIELDS):
+            fields = vprovider.fields()
+        else:
+            fields = QgsFields()
+        if self.getParameterValue(self.GEOMETRY):
+            fieldsCount = fields.count()
+            fields.append(QgsField("area",QVariant.Double,"double",16,2))
+            fields.append(QgsField("perimeter",QVariant.Double,"double",16,2))
+        allLinesList = []
+        features = QGisLayers.features(vlayer)
+        current = 0
+        total = 40.0 / float(len(features))
+        for inFeat in features:
+            inGeom = inFeat.geometry()
+            if inGeom.isMultipart():
+                allLinesList.extend(inGeom.asMultiPolyline())
+            else:
+                allLinesList.append(inGeom.asPolyline())
+            current += 1
+            progress.setPercentage(int(current * total))
+        progress.setPercentage(40)
+        allLines = MultiLineString(allLinesList)
+        allLines = allLines.union(Point(0,0))
+        progress.setPercentage(45)
+        polygons = list(polygonize([allLines]))
+        progress.setPercentage(50)
+        writer = output.getVectorWriter(fields, QGis.WKBPolygon, vlayer.crs() )
+        outFeat = QgsFeature()
+        current = 0
+        total = 50.0 / float(len(polygons))
+        for polygon in polygons:
+            outFeat.setGeometry(QgsGeometry.fromWkt( polygon.wkt ))
+            if self.getParameterValue(self.GEOMETRY):
+                outFeat.setAttributes([None]*fieldsCount + [ QVariant(polygon.area), QVariant(polygon.length)])
+            writer.addFeature(outFeat)
+            current += 1
+            progress.setPercentage(50+int(current * total))
+        del writer
+
+    def defineCharacteristics(self):
+        self.name = "Polygonize"
+        self.group = "Vector geometry tools"
+        self.addParameter(ParameterVector(self.INPUT, "Input layer",ParameterVector.VECTOR_TYPE_LINE))
+        self.addParameter(ParameterBoolean(self.FIELDS, "Keep table structure of line layer", False))
+        self.addParameter(ParameterBoolean(self.GEOMETRY, "Create geometry columns", True))
+        self.addOutput(OutputVector(self.OUTPUT, "Output layer"))
diff --git a/python/plugins/sextante/algs/QGISAlgorithmProvider.py b/python/plugins/sextante/algs/QGISAlgorithmProvider.py
@@ -16,6 +16,7 @@
 *                                                                         *
 ***************************************************************************
 """
+from sextante.algs.Polygonize import Polygonize
 
 __author__ = 'Victor Olaya'
 __date__ = 'December 2012'
@@ -130,7 +131,7 @@ def __init__(self):
                         # ------ native algs ------
                         AddTableField(), FieldsCalculator(), SaveSelectedFeatures(), JoinAttributes(),
                         AutoincrementalField(), Explode(), FieldsPyculator(), EquivalentNumField(),
-                        PointsLayerFromTable(), StatisticsByCategories(),
+                        PointsLayerFromTable(), StatisticsByCategories(), Polygonize(),
                         # ------ raster ------
                         CreateConstantRaster(), RasterLayerStatistics()
                         # ------ graphics ------