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[processing] port Random points along lines

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alexbruy committed Jul 21, 2017
1 parent f8b0c06 commit c7645a3884a3e9b98dd0669fd324c18578d7490a
@@ -84,6 +84,7 @@
from .PostGISExecuteSQL import PostGISExecuteSQL
from .RandomExtract import RandomExtract
from .RandomExtractWithinSubsets import RandomExtractWithinSubsets
from .RandomPointsAlongLines import RandomPointsAlongLines
from .RandomPointsExtent import RandomPointsExtent
from .RandomPointsLayer import RandomPointsLayer
from .RandomPointsPolygons import RandomPointsPolygons
@@ -144,7 +145,6 @@
# from .PointsDisplacement import PointsDisplacement
# from .PointsFromPolygons import PointsFromPolygons
# from .PointsFromLines import PointsFromLines
# from .RandomPointsAlongLines import RandomPointsAlongLines
# from .PointsToPaths import PointsToPaths
# from .SetVectorStyle import SetVectorStyle
# from .SetRasterStyle import SetRasterStyle
@@ -271,6 +271,7 @@ def getAlgs(self):
PostGISExecuteSQL(),
RandomExtract(),
RandomExtractWithinSubsets(),
RandomPointsAlongLines(),
RandomPointsExtent(),
RandomPointsLayer(),
RandomPointsPolygons(),
@@ -29,33 +29,37 @@
import random

from qgis.PyQt.QtCore import QVariant
from qgis.core import (QgsApplication,
from qgis.core import (QgsField,
QgsFeatureSink,
QgsFeature,
QgsFields,
QgsField,
QgsGeometry,
QgsSpatialIndex,
QgsPoint,
QgsPointXY,
QgsWkbTypes,
QgsDistanceArea,
QgsSpatialIndex,
QgsFeatureRequest,
QgsFeature,
QgsPointXY,
QgsMessageLog,
QgsDistanceArea,
QgsProject,
QgsProcessingUtils)
QgsProcessing,
QgsProcessingException,
QgsProcessingParameterNumber,
QgsProcessingParameterBoolean,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterFeatureSink,
QgsProcessingParameterDefinition)

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterNumber
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
from processing.tools import vector


class RandomPointsAlongLines(QgisAlgorithm):

VECTOR = 'VECTOR'
POINT_NUMBER = 'POINT_NUMBER'
INPUT = 'INPUT'
POINTS_NUMBER = 'POINTS_NUMBER'
MIN_DISTANCE = 'MIN_DISTANCE'
ADD_Z = 'ADD_Z'
ADD_M = 'ADD_M'
OUTPUT = 'OUTPUT'

def group(self):
@@ -65,13 +69,31 @@ def __init__(self):
super().__init__()

def initAlgorithm(self, config=None):
self.addParameter(ParameterVector(self.VECTOR,
self.tr('Input layer'), [dataobjects.TYPE_VECTOR_LINE]))
self.addParameter(ParameterNumber(self.POINT_NUMBER,
self.tr('Number of points'), 1, None, 1))
self.addParameter(ParameterNumber(self.MIN_DISTANCE,
self.tr('Minimum distance'), 0.0, None, 0.0))
self.addOutput(OutputVector(self.OUTPUT, self.tr('Random points'), datatype=[dataobjects.TYPE_VECTOR_POINT]))
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Input layer'),
[QgsProcessing.TypeVectorLine]))
self.addParameter(QgsProcessingParameterNumber(self.POINTS_NUMBER,
self.tr('Number of points'),
QgsProcessingParameterNumber.Integer,
1, False, 1, 1000000000))
self.addParameter(QgsProcessingParameterNumber(self.MIN_DISTANCE,
self.tr('Minimum distance between points'),
QgsProcessingParameterNumber.Double,
0, False, 0, 1000000000))
params = []
params.append(QgsProcessingParameterBoolean(self.ADD_Z,
self.tr('Add Z coordinate'),
False))
params.append(QgsProcessingParameterBoolean(self.ADD_M,
self.tr('Add M coordinate'),
False))
for p in params:
p.setFlags(p.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(p)

self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
self.tr('Random points'),
type=QgsProcessing.TypeVectorPoint))

def name(self):
return 'randompointsalongline'
@@ -80,35 +102,48 @@ def displayName(self):
return self.tr('Random points along line')

def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.VECTOR), context)
pointCount = float(self.getParameterValue(self.POINT_NUMBER))
minDistance = float(self.getParameterValue(self.MIN_DISTANCE))
source = self.parameterAsSource(parameters, self.INPUT, context)
pointCount = self.parameterAsDouble(parameters, self.POINTS_NUMBER, context)
minDistance = self.parameterAsDouble(parameters, self.MIN_DISTANCE, context)
addZ = self.parameterAsBool(parameters, self.ADD_Z, context)
addM = self.parameterAsBool(parameters, self.ADD_M, context)

fields = QgsFields()
fields.append(QgsField('id', QVariant.Int, '', 10, 0))
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.Point, layer.crs(), context)

wkbType = QgsWkbTypes.Point
if addZ:
wkbType = QgsWkbTypes.addZ(wkbType)
if addM:
wkbType = QgsWkbTypes.addM(wkbType)

(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, wkbType, source.sourceCrs())

nPoints = 0
nIterations = 0
maxIterations = pointCount * 200
featureCount = layer.featureCount()
featureCount = source.featureCount()
total = 100.0 / pointCount if pointCount else 1

index = QgsSpatialIndex()
points = dict()

da = QgsDistanceArea()
da.setSourceCrs(layer.sourceCrs())
da.setSourceCrs(source.sourceCrs())
da.setEllipsoid(QgsProject.instance().ellipsoid())

request = QgsFeatureRequest()

random.seed()

while nIterations < maxIterations and nPoints < pointCount:
if feedback.isCanceled():
break

# pick random feature
fid = random.randint(0, featureCount - 1)
f = next(layer.getFeatures(request.setFilterFid(fid).setSubsetOfAttributes([])))
f = next(source.getFeatures(request.setFilterFid(fid).setSubsetOfAttributes([])))
fGeom = f.geometry()

if fGeom.isMultipart():
@@ -135,23 +170,28 @@ def processAlgorithm(self, parameters, context, feedback):
ry = (startPoint.y() + d * endPoint.y()) / (1 + d)

# generate random point
pnt = QgsPointXY(rx, ry)
geom = QgsGeometry.fromPoint(pnt)
if vector.checkMinDistance(pnt, index, minDistance, points):
pnt = QgsPoint(rx, ry)
p = QgsPointXY(rx, ry)
if addZ:
pnt.addZValue(0.0)
if addM:
pnt.addMValue(0.0)
geom = QgsGeometry(pnt)
if vector.checkMinDistance(p, index, minDistance, points):
f = QgsFeature(nPoints)
f.initAttributes(1)
f.setFields(fields)
f.setAttribute('id', nPoints)
f.setGeometry(geom)
writer.addFeature(f, QgsFeatureSink.FastInsert)
sink.addFeature(f, QgsFeatureSink.FastInsert)
index.insertFeature(f)
points[nPoints] = pnt
points[nPoints] = p
nPoints += 1
feedback.setProgress(int(nPoints * total))
nIterations += 1

if nPoints < pointCount:
QgsMessageLog.logMessage(self.tr('Can not generate requested number of random points. '
'Maximum number of attempts exceeded.'), self.tr('Processing'), QgsMessageLog.INFO)
feedback.pushInfo(self.tr('Could not generate requested number of random points. '
'Maximum number of attempts exceeded.'))

del writer
return {self.OUTPUT: dest_id}

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