QGIS/python/plugins/fTools/tools/doRegPoints.py

#-----------------------------------------------------------
# 
# Generate Regular Points
#
# A QGIS plugin for generating a simple points
# shapefile of regularly spaced points. 
#
# 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 *
import ftools_utils
from qgis.core import *
from random import *
from math import *
from ui_frmRegPoints 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)
		self.setWindowTitle( self.tr("Regular points") )
		self.progressBar.setValue(0)
		mapCanvas = self.iface.mapCanvas()
		for i in range(mapCanvas.layerCount()):
			layer = mapCanvas.layer(i)
			self.inShape.addItem(layer.name())

	def accept(self):
		if not self.rdoCoordinates.isChecked() and self.inShape.currentText() == "":
			QMessageBox.information(self, self.tr("Generate Regular Points"), self.tr("Please specify input layer"))
		elif self.rdoCoordinates.isChecked() and (self.xMin.text() == "" or self.xMax.text() == "" or self.yMin.text() == "" or self.yMax.text() == ""):
			QMessageBox.information(self, self.tr("Generate Regular Points"), self.tr("Please properly specify extent coordinates"))
		elif self.outShape.text() == "":
			QMessageBox.information(self, self.tr("Generate Regular Points"), self.tr("Please specify output shapefile"))
		else:
			inName = self.inShape.currentText()
			outPath = self.outShape.text()
			self.outShape.clear()
			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)
			if self.rdoSpacing.isChecked(): value = self.spnSpacing.value()
			else: value = self.spnNumber.value()
			if self.chkRandom.isChecked(): offset = True
			else: offset = False
			if self.rdoBoundary.isChecked():
				mLayer = self.getMapLayerByName(unicode(inName))
				boundBox = mLayer.extent()
			else:
				boundBox = QgsRect(float(self.xMin.text()), float(self.yMin.text()), float(self.xMax.text()), float(self.yMax.text()))
			self.regularize(boundBox, outPath, offset, value, self.rdoSpacing.isChecked(), self.spnInset.value(), self.progressBar)
			addToTOC = QMessageBox.question(self, self.tr("Generate Regular Points"), self.tr("Created output point shapefile:\n%1\n\nNote: Layer has no associated coordinate system, please use the Projection Management Tool to specify spatial reference system.\n\nWould you like to add the new layer to the TOC?").arg( outPath ), 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 ) )
	
# 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, self.tr("Generate Regular Points"), self.tr("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
	
 
	def regularize(self, bound, outPath, offset, value, gridType, inset, progressBar):
		area = bound.width() * bound.height()
		if offset:
			seed()
		if gridType:
			pointSpacing = value
		else:
			# Calculate grid spacing
			pointSpacing = sqrt(area / value)
		outFeat = QgsFeature()
		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)
		#writer = QgsVectorFileWriter(unicode(outPath), "CP1250", fields, QGis.WKBPoint, None)
		idVar = 0
		count = 10.00
		add = 90.00 / (area / pointSpacing)
		y = bound.yMaximum() - inset
		while y >= bound.yMinimum():
			x = bound.xMinimum() + inset
			while x <= bound.xMaximum():
				if offset:
					pGeom = QgsGeometry().fromPoint(QgsPoint(uniform(x - (pointSpacing / 2.0), x + (pointSpacing / 2.0)), 
					uniform(y - (pointSpacing / 2.0), y + (pointSpacing / 2.0))))
				else:
					pGeom = QgsGeometry().fromPoint(QgsPoint(x, y))
				if pGeom.intersects(bound):
					outFeat.setGeometry(pGeom)
					outFeat.addAttribute(0, QVariant(idVar))
					writer.addFeature(outFeat)
					idVar = idVar + 1
					x = x + pointSpacing
					count = count + add
					progressBar.setValue(count)
			y = y - pointSpacing
		del writer