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[processing] add Points from polygons algorithm

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alexbruy committed Sep 13, 2013
1 parent 8481ebc commit 00e2f1fefcb3b9a18bea3593d77c7f365681bcf2
@@ -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):
@@ -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

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