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e7fe61e6b9
available or compatible QGIS version is used Some housekeeping in QGIS algorithms provider
181 lines
6.5 KiB
Python
181 lines
6.5 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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PointsFromLines.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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__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 PyQt4.QtCore import QVariant
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from qgis.core import QGis, QgsFeature, QgsFields, QgsField, QgsGeometry, QgsPoint
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from processing.tools import vector, raster, dataobjects
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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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class PointsFromLines(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) along line')
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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'), [ParameterVector.VECTOR_TYPE_LINE]))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Points along line')))
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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 = unicode(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('line_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(), QGis.WKBPoint, layer.crs())
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outFeature = QgsFeature()
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outFeature.setFields(fields)
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self.fid = 0
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self.lineId = 0
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self.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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if geom.isMultipart():
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lines = geom.asMultiPolyline()
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for line in lines:
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for i in xrange(len(line) - 1):
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p1 = line[i]
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p2 = line[i + 1]
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(x1, y1) = raster.mapToPixel(p1.x(), p1.y(),
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geoTransform)
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(x2, y2) = raster.mapToPixel(p2.x(), p2.y(),
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geoTransform)
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self.buildLine(x1, y1, x2, y2, geoTransform,
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writer, outFeature)
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else:
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points = geom.asPolyline()
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for i in xrange(len(points) - 1):
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p1 = points[i]
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p2 = points[i + 1]
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(x1, y1) = raster.mapToPixel(p1.x(), p1.y(), geoTransform)
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(x2, y2) = raster.mapToPixel(p2.x(), p2.y(), geoTransform)
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self.buildLine(x1, y1, x2, y2, geoTransform, writer,
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outFeature)
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self.pointId = 0
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self.lineId += 1
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progress.setPercentage(int(current * total))
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del writer
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def buildLine(self, startX, startY, endX, endY, geoTransform, writer, feature):
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if startX == endX:
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if startY > endY:
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(startY, endY) = (endY, startY)
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row = startX
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for col in xrange(startY, endY + 1):
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self.createPoint(row, col, geoTransform, writer, feature)
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elif startY == endY:
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if startX > endX:
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(startX, endX) = (endX, startX)
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col = startY
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for row in xrange(startX, endX + 1):
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self.createPoint(row, col, geoTransform, writer, feature)
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else:
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width = endX - startX
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height = endY - startY
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if width < 0:
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dx1 = -1
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dx2 = -1
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else:
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dx1 = 1
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dx2 = 1
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if height < 0:
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dy1 = -1
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else:
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dy1 = 1
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dy2 = 0
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longest = abs(width)
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shortest = abs(height)
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if not longest > shortest:
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(longest, shortest) = (shortest, longest)
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if height < 0:
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dy2 = -1
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else:
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dy2 = 1
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dx2 = 0
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err = longest / 2
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for i in xrange(longest + 1):
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self.createPoint(startX, startY, geoTransform, writer, feature)
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err += shortest
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if not err < longest:
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err = err - longest
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startX += dx1
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startY += dy1
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else:
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startX += dx2
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startY += dy2
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def createPoint(self, pX, pY, geoTransform, writer, feature):
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(x, y) = raster.pixelToMap(pX, pY, geoTransform)
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feature.setGeometry(QgsGeometry.fromPoint(QgsPoint(x, y)))
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feature['id'] = self.fid
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feature['line_id'] = self.lineId
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feature['point_id'] = self.pointId
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self.fid += 1
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self.pointId += 1
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writer.addFeature(feature)
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