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