[processing] add Points from polygons algorithm

alexbruy · alexbruy · commit 00e2f1fefcb3 · 2013-09-13T18:33:29.000+03:00
diff --git a/python/plugins/processing/algs/QGISAlgorithmProvider.py b/python/plugins/processing/algs/QGISAlgorithmProvider.py
@@ -88,6 +88,7 @@
 
 from processing.algs.PointsDisplacement import PointsDisplacement
 from sextante.algs.ZonalStatistics import ZonalStatistics
+from sextante.algs.PointsFromPolygons import PointsFromPolygons
 
 #from processing.algs.VectorLayerHistogram import VectorLayerHistogram
 #from processing.algs.VectorLayerScatterplot import VectorLayerScatterplot
@@ -143,7 +144,8 @@ def __init__(self):
                         #MeanAndStdDevPlot(), BarPlot(), PolarPlot()
                         # ------ vector ------
                         PointsDisplacement(),
-                        ZonalStatistics()
+                        ZonalStatistics(),
+                        PointsFromPolygons()
                         ]
 
     def initializeSettings(self):
diff --git a/python/plugins/sextante/algs/PointsFromPolygons.py b/python/plugins/sextante/algs/PointsFromPolygons.py
@@ -0,0 +1,120 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    PointsFromPolygons.py
+    ---------------------
+    Date                 : August 2013
+    Copyright            : (C) 2013 by Alexander Bruy
+    Email                : alexander dot bruy 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__ = 'Alexander Bruy'
+__date__ = 'August 2013'
+__copyright__ = '(C) 2013, Alexander Bruy'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+from PyQt4.QtCore import *
+
+from osgeo import gdal
+
+from qgis.core import *
+
+from sextante.core.GeoAlgorithm import GeoAlgorithm
+from sextante.core.QGisLayers import QGisLayers
+
+from sextante.parameters.ParameterRaster import ParameterRaster
+from sextante.parameters.ParameterVector import ParameterVector
+
+from sextante.outputs.OutputVector import OutputVector
+
+from sextante.algs import QGISUtils as utils
+
+class PointsFromPolygons(GeoAlgorithm):
+
+    INPUT_RASTER = "INPUT_RASTER"
+    RASTER_BAND = "RASTER_BAND"
+    INPUT_VECTOR = "INPUT_VECTOR"
+    OUTPUT_LAYER = "OUTPUT_LAYER"
+
+    def defineCharacteristics(self):
+        self.name = "Points from polygons"
+        self.group = "Vector geometry tools"
+
+        self.addParameter(ParameterRaster(self.INPUT_RASTER, "Raster layer"))
+        self.addParameter(ParameterVector(self.INPUT_VECTOR, "Vector layer", [ParameterVector.VECTOR_TYPE_POLYGON]))
+        self.addOutput(OutputVector(self.OUTPUT_LAYER, "Output layer"))
+
+    def processAlgorithm(self, progress):
+        layer = QGisLayers.getObjectFromUri(self.getParameterValue(self.INPUT_VECTOR))
+
+        rasterPath = unicode(self.getParameterValue(self.INPUT_RASTER))
+
+        rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
+        geoTransform = rasterDS.GetGeoTransform()
+        rasterDS = None
+
+        fields = QgsFields()
+        fields.append(QgsField("id", QVariant.Int, "", 10, 0))
+        fields.append(QgsField("poly_id", QVariant.Int, "", 10, 0))
+        fields.append(QgsField("point_id", QVariant.Int, "", 10, 0))
+
+        writer = self.getOutputFromName(self.OUTPUT_LAYER).getVectorWriter(fields.toList(), QGis.WKBPoint, layer.crs())
+
+        outFeature = QgsFeature()
+        outFeature.setFields(fields)
+        point = QgsPoint()
+
+        fid = 0
+        polyId = 0
+        pointId = 0
+
+        current = 0
+        features = QGisLayers.features(layer)
+        total = 100.0 / len(features)
+        for f in features:
+            geom = f.geometry()
+            bbox = geom.boundingBox()
+
+            xMin = bbox.xMinimum()
+            xMax = bbox.xMaximum()
+            yMin = bbox.yMinimum()
+            yMax = bbox.yMaximum()
+
+            startRow, startColumn = utils.mapToPixel(xMin, yMax, geoTransform)
+            endRow, endColumn = utils.mapToPixel(xMax, yMin, geoTransform)
+
+            for row in xrange(startRow, endRow + 1):
+                for col in xrange(startColumn, endColumn + 1):
+                    x, y = utils.pixelToMap(row, col, geoTransform)
+                    point.setX(x)
+                    point.setY(y)
+
+                    if geom.contains(point):
+                        outFeature.setGeometry(QgsGeometry.fromPoint(point))
+                        outFeature["id"] = fid
+                        outFeature["poly_id"] = polyId
+                        outFeature["point_id"] = pointId
+
+                        fid += 1
+                        pointId +=1
+
+                        writer.addFeature(outFeature)
+
+            pointId = 0
+            polyId += 1
+
+            current += 1
+            progress.setPercentage(int(current * total))
+
+        del writer
+
