QGIS/python/plugins/processing/algs/qgis/RandomPointsExtent.py

148 lines
5.8 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
RandomPointsExtent.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. *
* *
***************************************************************************
"""
from builtins import str
__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 os
import random
from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtCore import QVariant
from qgis.core import (QgsField,
QgsFeatureSink,
QgsFeature,
QgsFields,
QgsGeometry,
QgsPointXY,
QgsWkbTypes,
QgsSpatialIndex,
QgsProcessing,
QgsProcessingException,
QgsProcessingParameterExtent,
QgsProcessingParameterNumber,
QgsProcessingParameterCrs,
QgsProcessingParameterFeatureSink,
QgsProcessingParameterDefinition)
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 RandomPointsExtent(QgisAlgorithm):
EXTENT = 'EXTENT'
POINTS_NUMBER = 'POINTS_NUMBER'
MIN_DISTANCE = 'MIN_DISTANCE'
TARGET_CRS = 'TARGET_CRS'
OUTPUT = 'OUTPUT'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'random_points.png'))
def group(self):
return self.tr('Vector creation')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterExtent(self.EXTENT, self.tr('Input extent')))
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))
self.addParameter(QgsProcessingParameterCrs(self.TARGET_CRS,
self.tr('Target CRS'),
'ProjectCrs'))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
self.tr('Random points'),
type=QgsProcessing.TypeVectorPoint))
def name(self):
return 'randompointsinextent'
def displayName(self):
return self.tr('Random points in extent')
def processAlgorithm(self, parameters, context, feedback):
pointCount = self.parameterAsDouble(parameters, self.POINTS_NUMBER, context)
minDistance = self.parameterAsDouble(parameters, self.MIN_DISTANCE, context)
crs = self.parameterAsCrs(parameters, self.TARGET_CRS, context)
bbox = self.parameterAsExtent(parameters, self.EXTENT, context, crs)
extent = QgsGeometry().fromRect(bbox)
fields = QgsFields()
fields.append(QgsField('id', QVariant.Int, '', 10, 0))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.Point, crs)
nPoints = 0
nIterations = 0
maxIterations = pointCount * 200
total = 100.0 / pointCount if pointCount else 1
index = QgsSpatialIndex()
points = dict()
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.fromPoint(p)
if geom.within(extent) and \
vector.checkMinDistance(p, index, minDistance, points):
f = QgsFeature(nPoints)
f.initAttributes(1)
f.setFields(fields)
f.setAttribute('id', nPoints)
f.setGeometry(geom)
sink.addFeature(f, QgsFeatureSink.FastInsert)
index.insertFeature(f)
points[nPoints] = p
nPoints += 1
feedback.setProgress(int(nPoints * total))
nIterations += 1
if nPoints < pointCount:
feedback.pushInfo(self.tr('Could not generate requested number of random points. '
'Maximum number of attempts exceeded.'))
return {self.OUTPUT: dest_id}