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196e15a0ff
Random Points in Polygon algorithm Instead, use a standard numeric parameter which accepts data-defined expression values Fixes #27640
245 lines
10 KiB
Python
245 lines
10 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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RandomPointsPolygons.py
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---------------------
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Date : April 2014
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Copyright : (C) 2014 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__ = 'April 2014'
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__copyright__ = '(C) 2014, Alexander Bruy'
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import os
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import random
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from qgis.PyQt.QtCore import QVariant
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from qgis.core import (QgsApplication,
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QgsField,
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QgsFeatureSink,
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QgsFeature,
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QgsFields,
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QgsGeometry,
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QgsPointXY,
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QgsWkbTypes,
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QgsSpatialIndex,
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QgsExpression,
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QgsDistanceArea,
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QgsPropertyDefinition,
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QgsProcessing,
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QgsProcessingException,
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QgsProcessingParameters,
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QgsProcessingParameterDefinition,
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QgsProcessingParameterNumber,
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QgsProcessingParameterDistance,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterFeatureSink,
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QgsProcessingParameterExpression,
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QgsProcessingParameterEnum)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.tools import vector
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class RandomPointsPolygons(QgisAlgorithm):
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INPUT = 'INPUT'
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VALUE = 'VALUE'
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EXPRESSION = 'EXPRESSION'
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MIN_DISTANCE = 'MIN_DISTANCE'
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STRATEGY = 'STRATEGY'
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OUTPUT = 'OUTPUT'
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def icon(self):
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return QgsApplication.getThemeIcon("/algorithms/mAlgorithmRandomPointsWithinPolygon.svg")
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def svgIconPath(self):
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return QgsApplication.iconPath("/algorithms/mAlgorithmRandomPointsWithinPolygon.svg")
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def group(self):
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return self.tr('Vector creation')
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def groupId(self):
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return 'vectorcreation'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.strategies = [self.tr('Points count'),
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self.tr('Points density')]
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self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
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self.tr('Input layer'),
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[QgsProcessing.TypeVectorPolygon]))
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self.addParameter(QgsProcessingParameterEnum(self.STRATEGY,
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self.tr('Sampling strategy'),
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self.strategies,
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False,
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0))
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value_param = QgsProcessingParameterNumber(self.VALUE,
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self.tr('Point count or density'),
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QgsProcessingParameterNumber.Double,
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1,
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minValue=0)
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value_param.setIsDynamic(True)
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value_param.setDynamicLayerParameterName(self.INPUT)
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value_param.setDynamicPropertyDefinition(
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QgsPropertyDefinition("Value", self.tr("Point count or density"), QgsPropertyDefinition.Double))
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self.addParameter(value_param)
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# deprecated expression parameter - overrides value parameter if set
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exp_param = QgsProcessingParameterExpression(self.EXPRESSION,
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self.tr('Expression'), optional=True,
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parentLayerParameterName=self.INPUT)
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exp_param.setFlags(exp_param.flags() | QgsProcessingParameterDefinition.FlagHidden)
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self.addParameter(exp_param)
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self.addParameter(QgsProcessingParameterDistance(self.MIN_DISTANCE,
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self.tr('Minimum distance between points'),
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None, self.INPUT, True, 0, 1000000000))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
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self.tr('Random points'),
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type=QgsProcessing.TypeVectorPoint))
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def name(self):
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return 'randompointsinsidepolygons'
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def displayName(self):
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return self.tr('Random points inside polygons')
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def processAlgorithm(self, parameters, context, feedback):
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source = self.parameterAsSource(parameters, self.INPUT, context)
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if source is None:
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raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
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strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
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if self.MIN_DISTANCE in parameters and parameters[self.MIN_DISTANCE] is not None:
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minDistance = self.parameterAsDouble(parameters, self.MIN_DISTANCE, context)
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else:
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minDistance = None
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expressionContext = self.createExpressionContext(parameters, context, source)
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dynamic_value = QgsProcessingParameters.isDynamic(parameters, "VALUE")
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value_property = None
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if self.EXPRESSION in parameters and parameters[self.EXPRESSION] is not None:
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expression = QgsExpression(self.parameterAsString(parameters, self.EXPRESSION, context))
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value = None
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if expression.hasParserError():
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raise QgsProcessingException(expression.parserErrorString())
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expression.prepare(expressionContext)
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else:
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expression = None
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if dynamic_value:
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value_property = parameters["VALUE"]
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value = self.parameterAsDouble(parameters, self.VALUE, context)
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fields = QgsFields()
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fields.append(QgsField('id', QVariant.Int, '', 10, 0))
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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fields, QgsWkbTypes.Point, source.sourceCrs(),
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QgsFeatureSink.RegeneratePrimaryKey)
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if sink is None:
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raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
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da = QgsDistanceArea()
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da.setSourceCrs(source.sourceCrs(), context.transformContext())
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da.setEllipsoid(context.project().ellipsoid())
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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current_progress = 0
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pointId = 0
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for current, f in enumerate(source.getFeatures()):
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if feedback.isCanceled():
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break
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if not f.hasGeometry():
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continue
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current_progress = total * current
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feedback.setProgress(current_progress)
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this_value = value
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if value_property is not None or expression is not None:
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expressionContext.setFeature(f)
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if value_property:
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this_value, _ = value_property.valueAsDouble(expressionContext, value)
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else:
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this_value = expression.evaluate(expressionContext)
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if expression.hasEvalError():
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feedback.pushInfo(
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self.tr('Evaluation error for feature ID {}: {}').format(f.id(), expression.evalErrorString()))
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continue
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fGeom = f.geometry()
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engine = QgsGeometry.createGeometryEngine(fGeom.constGet())
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engine.prepareGeometry()
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bbox = fGeom.boundingBox()
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if strategy == 0:
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pointCount = int(this_value)
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else:
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pointCount = int(round(this_value * da.measureArea(fGeom)))
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if pointCount == 0:
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feedback.pushInfo("Skip feature {} as number of points for it is 0.".format(f.id()))
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continue
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index = None
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if minDistance:
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index = QgsSpatialIndex()
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points = dict()
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nPoints = 0
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nIterations = 0
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maxIterations = pointCount * 200
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feature_total = total / pointCount if pointCount else 1
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random.seed()
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while nIterations < maxIterations and nPoints < pointCount:
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if feedback.isCanceled():
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break
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rx = bbox.xMinimum() + bbox.width() * random.random()
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ry = bbox.yMinimum() + bbox.height() * random.random()
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p = QgsPointXY(rx, ry)
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geom = QgsGeometry.fromPointXY(p)
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if engine.contains(geom.constGet()) and \
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(not minDistance or vector.checkMinDistance(p, index, minDistance, points)):
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f = QgsFeature(nPoints)
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f.initAttributes(1)
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f.setFields(fields)
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f.setAttribute('id', pointId)
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f.setGeometry(geom)
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sink.addFeature(f, QgsFeatureSink.FastInsert)
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if minDistance:
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index.addFeature(f)
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points[nPoints] = p
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nPoints += 1
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pointId += 1
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feedback.setProgress(current_progress + int(nPoints * feature_total))
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nIterations += 1
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if nPoints < pointCount:
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feedback.pushInfo(self.tr('Could not generate requested number of random '
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'points. Maximum number of attempts exceeded.'))
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feedback.setProgress(100)
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return {self.OUTPUT: dest_id}
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