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a05b610a8b
Wherever possible use prepared geometry engines for intersects type tests, as it's much faster
123 lines
4.7 KiB
Python
123 lines
4.7 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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PointsFromPolygons.py
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---------------------
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Date : August 2013
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Copyright : (C) 2013 by Alexander Bruy
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Email : alexander dot bruy at gmail dot com
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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 builtins import str
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from builtins import range
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__author__ = 'Alexander Bruy'
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__date__ = 'August 2013'
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__copyright__ = '(C) 2013, Alexander Bruy'
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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 osgeo import gdal
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from qgis.core import Qgis, QgsFields, QgsField, QgsFeature, QgsPoint, QgsGeometry, QgsWkbTypes, QgsPointV2
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from qgis.PyQt.QtCore import QVariant
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.parameters import ParameterRaster
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from processing.core.parameters import ParameterVector
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector, raster
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class PointsFromPolygons(GeoAlgorithm):
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INPUT_RASTER = 'INPUT_RASTER'
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RASTER_BAND = 'RASTER_BAND'
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INPUT_VECTOR = 'INPUT_VECTOR'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Generate points (pixel centroids) inside polygons')
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self.group, self.i18n_group = self.trAlgorithm('Vector analysis tools')
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self.addParameter(ParameterRaster(self.INPUT_RASTER,
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self.tr('Raster layer')))
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self.addParameter(ParameterVector(self.INPUT_VECTOR,
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self.tr('Vector layer'), [dataobjects.TYPE_VECTOR_POLYGON]))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Points from polygons'), datatype=[dataobjects.TYPE_VECTOR_POINT]))
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def processAlgorithm(self, progress):
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layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT_VECTOR))
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rasterPath = str(self.getParameterValue(self.INPUT_RASTER))
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rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
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geoTransform = rasterDS.GetGeoTransform()
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rasterDS = None
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fields = QgsFields()
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fields.append(QgsField('id', QVariant.Int, '', 10, 0))
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fields.append(QgsField('poly_id', QVariant.Int, '', 10, 0))
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fields.append(QgsField('point_id', QVariant.Int, '', 10, 0))
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writer = self.getOutputFromName(self.OUTPUT_LAYER).getVectorWriter(
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fields.toList(), QgsWkbTypes.Point, layer.crs())
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outFeature = QgsFeature()
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outFeature.setFields(fields)
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fid = 0
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polyId = 0
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pointId = 0
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features = vector.features(layer)
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total = 100.0 / len(features)
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for current, f in enumerate(features):
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geom = f.geometry()
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bbox = geom.boundingBox()
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xMin = bbox.xMinimum()
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xMax = bbox.xMaximum()
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yMin = bbox.yMinimum()
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yMax = bbox.yMaximum()
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(startRow, startColumn) = raster.mapToPixel(xMin, yMax, geoTransform)
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(endRow, endColumn) = raster.mapToPixel(xMax, yMin, geoTransform)
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# use prepared geometries for faster intersection tests
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engine = QgsGeometry.createGeometryEngine(geom.geometry())
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engine.prepareGeometry()
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for row in range(startRow, endRow + 1):
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for col in range(startColumn, endColumn + 1):
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(x, y) = raster.pixelToMap(row, col, geoTransform)
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point = QgsPointV2()
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point.setX(x)
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point.setY(y)
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if engine.contains(point):
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outFeature.setGeometry(QgsGeometry(point))
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outFeature['id'] = fid
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outFeature['poly_id'] = polyId
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outFeature['point_id'] = pointId
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fid += 1
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pointId += 1
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writer.addFeature(outFeature)
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pointId = 0
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polyId += 1
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progress.setPercentage(int(current * total))
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del writer
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