#-----------------------------------------------------------
#
# Generate Random Points
#
# A QGIS plugin for generating a simple random points
# shapefile.
#
# Copyright (C) 2008 Carson Farmer
#
# EMAIL: carson.farmer (at) gmail.com
# WEB : www.geog.uvic.ca/spar/carson
#
#-----------------------------------------------------------
#
# licensed under the terms of GNU GPL 2
#
# 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.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
#---------------------------------------------------------------------
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.core import *
from random import *
import math, ftools_utils
from ui_frmRandPoints import Ui_Dialog
class Dialog(QDialog, Ui_Dialog):
def __init__(self, iface):
QDialog.__init__(self)
self.iface = iface
self.setupUi(self)
QObject.connect(self.toolOut, SIGNAL("clicked()"), self.outFile)
QObject.connect(self.inShape, SIGNAL("currentIndexChanged(QString)"), self.update)
self.progressBar.setValue(0)
self.setWindowTitle("Random points")
mapCanvas = self.iface.mapCanvas()
for i in range(mapCanvas.layerCount()):
layer = mapCanvas.layer(i)
if (layer.type() == layer.VectorLayer and layer.geometryType() == QGis.Polygon) or layer.type() == layer.RasterLayer:
self.inShape.addItem(layer.name())
# If input layer is changed, update field list
def update(self, inputLayer):
self.cmbField.clear()
changedLayer = self.getMapLayerByName(inputLayer)
if changedLayer.type() == changedLayer.VectorLayer:
self.rdoStratified.setEnabled(True)
self.rdoDensity.setEnabled(True)
self.rdoField.setEnabled(True)
self.label_4.setEnabled(True)
changedLayer = self.getVectorLayerByName(inputLayer)
changedFields = self.getFieldList(changedLayer)
for i in changedFields:
self.cmbField.addItem(unicode(changedFields[i].name()))
else:
self.rdoUnstratified.setChecked(True)
self.rdoStratified.setEnabled(False)
self.rdoDensity.setEnabled(False)
self.rdoField.setEnabled(False)
self.spnStratified.setEnabled(False)
self.spnDensity.setEnabled(False)
self.cmbField.setEnabled(False)
self.label_4.setEnabled(False)
# when 'OK' button is pressed, gather required inputs, and initiate random points generation
def accept(self):
if self.inShape.currentText() == "":
QMessageBox.information(self, "Random Points", "No input layer specified")
elif self.outShape.text() == "":
QMessageBox.information(self, "Random Points", "Please specify output shapefile")
else:
inName = self.inShape.currentText()
self.progressBar.setValue(1)
outPath = self.outShape.text()
self.progressBar.setValue(2.5)
if outPath.contains("\\"):
outName = outPath.right((outPath.length() - outPath.lastIndexOf("\\")) - 1)
else:
outName = outPath.right((outPath.length() - outPath.lastIndexOf("/")) - 1)
if outName.endsWith(".shp"):
outName = outName.left(outName.length() - 4)
self.progressBar.setValue(5)
mLayer = self.getMapLayerByName(unicode(inName))
if mLayer.type() == mLayer.VectorLayer:
inLayer = QgsVectorLayer(unicode(mLayer.source(),'latin1'), unicode(mLayer.name(),'latin1'), unicode(mLayer.dataProvider().name()))
if self.rdoUnstratified.isChecked():
design = "unstratified"
value = self.spnUnstratified.value()
elif self.rdoStratified.isChecked():
design = "stratified"
value = self.spnStratified.value()
elif self.rdoDensity.isChecked():
design = "density"
value = self.spnDensity.value()
else:
design = "field"
value = unicode(self.cmbField.currentText())
elif mLayer.type() == mLayer.RasterLayer:
inLayer = QgsRasterLayer(unicode(mLayer.source(),'latin1'), unicode(mLayer.name(),'latin1'))
design = "unstratified"
value = self.spnUnstratified.value()
else:
QMessageBox.information(self, "Random Points", "Unknown layer type...")
if self.chkMinimum.isChecked():
minimum = self.spnMinimum.value()
else:
minimum = 0.00
self.progressBar.setValue(10)
self.randomize(inLayer, outPath, minimum, design, value, self.progressBar)
self.progressBar.setValue(100)
self.outShape.clear()
addToTOC = QMessageBox.question(self, "Random Points", "Created output point Shapefile:\n" + outPath
+ "\n\nWould you like to add the new layer to the TOC?", QMessageBox.Yes, QMessageBox.No, QMessageBox.NoButton)
if addToTOC == QMessageBox.Yes:
self.vlayer = QgsVectorLayer(outPath, unicode(outName), "ogr")
QgsMapLayerRegistry.instance().addMapLayer(self.vlayer)
self.progressBar.setValue(0)
def outFile(self):
self.outShape.clear()
( self.shapefileName, self.encoding ) = ftools_utils.saveDialog( self )
if self.shapefileName is None or self.encoding is None:
return
self.outShape.setText( QString( self.shapefileName ) )
# combine all polygons in layer to create single polygon (slow for complex polygons)
def createSinglePolygon(self, vlayer, progressBar):
provider = vlayer.dataProvider()
allAttrs = provider.attributeIndexes()
provider.select(allAttrs)
feat = QgsFeature()
geom = QgsGeometry()
geom2 = QgsGeometry()
provider.nextFeature(feat)
geom = feat.geometry()
count = 10.00
add = 40.00 / provider.featureCount()
provider.rewind()
provider.nextFeature(feat)
geom = QgsGeometry(feat.geometry())
while provider.nextFeature(feat):
geom = geom.combine(QgsGeometry( feat.geometry() ))
count = count + add
progressBar.setValue(count)
return geom
# Generate list of random points
def simpleRandom(self, n, bound, xmin, xmax, ymin, ymax):
seed()
points = []
i = 1
while i <= n:
pGeom = QgsGeometry().fromPoint(QgsPoint(xmin + (xmax-xmin) * random(), ymin + (ymax-ymin) * random()))
if pGeom.intersects(bound):
points.append(pGeom)
i = i + 1
return points
# Get vector layer by name from TOC
def getVectorLayerByName(self, myName):
mc = self.iface.mapCanvas()
nLayers = mc.layerCount()
for l in range(nLayers):
layer = mc.layer(l)
if layer.name() == unicode(myName):
vlayer = QgsVectorLayer(unicode(layer.source()), unicode(myName), unicode(layer.dataProvider().name()))
if vlayer.isValid():
return vlayer
else:
QMessageBox.information(self, "Generate Centroids", "Vector layer is not valid")
# Get map layer by name from TOC
def getMapLayerByName(self, myName):
mc = self.iface.mapCanvas()
nLayers = mc.layerCount()
for l in range(nLayers):
layer = mc.layer(l)
if layer.name() == unicode(myName):
if layer.isValid():
return layer
# Retrieve the field map of a vector Layer
def getFieldList(self, vlayer):
fProvider = vlayer.dataProvider()
feat = QgsFeature()
allAttrs = fProvider.attributeIndexes()
fProvider.select(allAttrs)
myFields = fProvider.fields()
return myFields
def randomize(self, inLayer, outPath, minimum, design, value, progressBar):
outFeat = QgsFeature()
if design == "unstratified":
ext = inLayer.extent()
if inLayer.type() == inLayer.RasterLayer: bound = ext
else: bound = self.createSinglePolygon(inLayer, progressBar)
points = self.simpleRandom(int(value), bound, ext.xMinimum(), ext.xMaximum(), ext.yMinimum(), ext.yMaximum())
progressBar.setValue(70)
else: points = self.loopThruPolygons(inLayer, value, design, progressBar)
fields = { 0 : QgsField("ID", QVariant.Int) }
check = QFile(self.shapefileName)
if check.exists():
if not QgsVectorFileWriter.deleteShapeFile(self.shapefileName):
return
writer = QgsVectorFileWriter(self.shapefileName, self.encoding, fields, QGis.WKBPoint, None)
idVar = 0
count = 70.00
add = 30.00 / len(points)
for i in points:
outFeat.setGeometry(i)
outFeat.addAttribute(0, QVariant(idVar))
writer.addFeature(outFeat)
idVar = idVar + 1
count = count + add
progressBar.setValue(count)
del writer
#
def loopThruPolygons(self, inLayer, numRand, design, progressBar):
sProvider = inLayer.dataProvider()
sAllAttrs = sProvider.attributeIndexes()
sProvider.select(sAllAttrs)
sFeat = QgsFeature()
sGeom = QgsGeometry()
sPoints = []
if design == "field":
for (i, attr) in sProvider.fields().iteritems():
if (unicode(numRand) == attr.name()): index = i #get input field index
count = 10.00
add = 60.00 / sProvider.featureCount()
while sProvider.nextFeature(sFeat):
sGeom = sFeat.geometry()
if design == "density":
sDistArea = QgsDistanceArea()
value = int(round(numRand * sDistArea.measure(sGeom)))
elif design == "field":
sAtMap = sFeat.attributeMap()
value = sAtMap[index].toInt()[0]
else:
value = numRand
sExt = sGeom.boundingBox()
sPoints.extend(self.simpleRandom(value, sGeom, sExt.xMinimum(), sExt.xMaximum(), sExt.yMinimum(), sExt.yMaximum()))
count = count + add
progressBar.setValue(count)
return sPoints