mirror of
https://github.com/qgis/QGIS.git
synced 2025-02-25 00:58:06 -05:00
139 lines
5.1 KiB
Python
139 lines
5.1 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
"""
|
|
***************************************************************************
|
|
RandomPointsAlongLines.py
|
|
---------------------
|
|
Date : April 2014
|
|
Copyright : (C) 2014 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__ = 'April 2014'
|
|
__copyright__ = '(C) 2014, Alexander Bruy'
|
|
|
|
# This will get replaced with a git SHA1 when you do a git archive
|
|
|
|
__revision__ = '$Format:%H$'
|
|
|
|
import math
|
|
import random
|
|
|
|
from PyQt4.QtCore import *
|
|
|
|
from qgis.core import *
|
|
|
|
from processing.core.GeoAlgorithm import GeoAlgorithm
|
|
from processing.core.ProcessingLog import ProcessingLog
|
|
from processing.parameters.ParameterVector import ParameterVector
|
|
from processing.parameters.ParameterNumber import ParameterNumber
|
|
from processing.parameters.ParameterSelection import ParameterSelection
|
|
from processing.outputs.OutputVector import OutputVector
|
|
from processing.tools import dataobjects, vector
|
|
|
|
|
|
class RandomPointsAlongLines(GeoAlgorithm):
|
|
|
|
VECTOR = 'VECTOR'
|
|
POINT_NUMBER = 'POINT_NUMBER'
|
|
MIN_DISTANCE = 'MIN_DISTANCE'
|
|
OUTPUT = 'OUTPUT'
|
|
|
|
def defineCharacteristics(self):
|
|
self.name = 'Random points along line'
|
|
self.group = 'Vector creation tools'
|
|
self.addParameter(ParameterVector(self.VECTOR,
|
|
'Input layer',[ParameterVector.VECTOR_TYPE_LINE]))
|
|
self.addParameter(ParameterNumber
|
|
(self.POINT_NUMBER, 'Number of points', 1, 9999999, 1))
|
|
self.addParameter(ParameterNumber(
|
|
self.MIN_DISTANCE, 'Minimum distance', 0.0, 9999999.0, 0.0))
|
|
self.addOutput(OutputVector(self.OUTPUT, 'Random points'))
|
|
|
|
def processAlgorithm(self, progress):
|
|
layer = dataobjects.getObjectFromUri(
|
|
self.getParameterValue(self.VECTOR))
|
|
pointCount = float(self.getParameterValue(self.POINT_NUMBER))
|
|
minDistance = float(self.getParameterValue(self.MIN_DISTANCE))
|
|
|
|
fields = QgsFields()
|
|
fields.append(QgsField('id', QVariant.Int, '', 10, 0))
|
|
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
|
|
fields, QGis.WKBPoint, layer.dataProvider().crs())
|
|
|
|
nPoints = 0
|
|
nIterations = 0
|
|
maxIterations = pointCount * 200
|
|
featureCount = layer.featureCount()
|
|
total = 100.0 / pointCount
|
|
|
|
index = QgsSpatialIndex()
|
|
points = dict()
|
|
|
|
da = QgsDistanceArea()
|
|
request = QgsFeatureRequest()
|
|
|
|
random.seed()
|
|
|
|
while nIterations < maxIterations and nPoints < pointCount:
|
|
# pick random feature
|
|
fid = random.randint(0, featureCount - 1)
|
|
f = layer.getFeatures(request.setFilterFid(fid)).next()
|
|
fGeom = QgsGeometry(f.geometry())
|
|
|
|
if fGeom.isMultipart():
|
|
lines = fGeom.asMultiPolyline()
|
|
# pick random line
|
|
lineId = random.randint(0, len(lines) - 1)
|
|
vertices = lines[lineId]
|
|
else:
|
|
vertices = fGeom.asPolyline()
|
|
|
|
# pick random segment
|
|
if len(vertices) == 2:
|
|
vid = 0
|
|
else:
|
|
vid = random.randint(0, len(vertices) - 2)
|
|
startPoint = vertices[vid]
|
|
endPoint = vertices[vid + 1]
|
|
length = da.measureLine(startPoint, endPoint)
|
|
dist = length * random.random()
|
|
|
|
if dist > minDistance:
|
|
d = dist / (length - dist)
|
|
rx = (startPoint.x() + d * endPoint.x()) / (1 + d)
|
|
ry = (startPoint.y() + d * endPoint.y()) / (1 + d)
|
|
|
|
# generate random point
|
|
pnt = QgsPoint(rx, ry)
|
|
geom = QgsGeometry.fromPoint(pnt)
|
|
if vector.checkMinDistance(pnt, index, minDistance, points):
|
|
f = QgsFeature(nPoints)
|
|
f.initAttributes(1)
|
|
f.setFields(fields)
|
|
f.setAttribute('id', nPoints)
|
|
f.setGeometry(geom)
|
|
writer.addFeature(f)
|
|
index.insertFeature(f)
|
|
points[nPoints] = pnt
|
|
nPoints += 1
|
|
progress.setPercentage(int(nPoints * total))
|
|
nIterations += 1
|
|
|
|
if nPoints < pointCount:
|
|
ProcessingLog.addToLog(
|
|
ProcessingLog.LOG_INFO,
|
|
'Can not generate requested number of random points. Maximum '
|
|
'number of attempts exceeded.')
|
|
|
|
del writer
|