QGIS/python/plugins/ftools/tools/doVectorGrid.py

#-----------------------------------------------------------
# 
# Generate Vector Grid
#
# A QGIS plugin for generating a line or polygon grid
#
# 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 frmVectorGrid 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.spnX, SIGNAL("valueChanged(double)"), self.offset)
		#QObject.connect(self.inShape, SIGNAL("currentIndexChanged(QString)"), self.updateInput)
		QObject.connect(self.btnUpdate, SIGNAL("clicked()"), self.updateInput)
		self.setWindowTitle("Vector grid")
		self.xMin.setValidator(QDoubleValidator(self.xMin))
		self.xMax.setValidator(QDoubleValidator(self.xMax))
		self.yMin.setValidator(QDoubleValidator(self.yMin))
		self.yMax.setValidator(QDoubleValidator(self.yMax))
		layers = ftools_utils.getLayerNames( 
		[ QGis.Point, QGis.Line, QGis.Polygon ] )
		for layer in layers:
			self.inShape.addItem( layer )

	def offset(self, value):
		if self.chkLock.isChecked():
			self.spnY.setValue(value)

	def updateInput( self ):
		mLayerName = self.inShape.currentText()
		if not mLayerName == "":
			mLayer = self.getMapLayerByName( unicode( mLayerName ) )
			self.inLayer = mLayer
			boundBox = mLayer.extent()
			self.updateExtents( boundBox )
		
	def updateExtents( self, boundBox ):
		self.xMin.setText( unicode( boundBox.xMinimum() ) )
		self.yMin.setText( unicode( boundBox.yMinimum() ) )
		self.xMax.setText( unicode( boundBox.xMaximum() ) )
		self.yMax.setText( unicode( boundBox.yMaximum() ) )

	def accept(self):
		if self.xMin.text() == "" or self.xMax.text() == "" or self.yMin.text() == "" or self.yMax.text() == "":
			QMessageBox.information(self, "Vector grid", "Please specify valid extent coordinates")
		elif self.outShape.text() == "":
			QMessageBox.information(self, "Vector grid", "Please specify output shapefile")
		else:
			try:
				boundBox = QgsRectangle( 
				float( self.xMin.text() ),
				float( self.yMin.text() ),
				float( self.xMax.text() ),
				float( self.yMax.text() ) )
			except:
				QMessageBox.information(self, "Vector grid", "Invalid extent coordinates entered")
			xSpace = self.spnX.value()
			ySpace = self.spnY.value()
			if self.rdoPolygons.isChecked(): polygon = True
			else: polygon = False
			self.outShape.clear()
			self.compute( boundBox, xSpace, ySpace, polygon )
			addToTOC = QMessageBox.question(self, 
			"Generate Vector Grid", "Created output Shapefile:\n" + outPath 
			+ "\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?", 
			QMessageBox.Yes, QMessageBox.No, QMessageBox.NoButton)
			if addToTOC == QMessageBox.Yes:
				ftools_utils.addShapeToCanvas( self.shapefileName )
			self.progressBar.setValue( 0 )

	def compute( self, bound, xOffset, yOffset, polygon ):
		if polygon:
			fields = {0:QgsField("ID", QVariant.Int), 1:QgsField("XMIN", QVariant.Double), 2:QgsField("XMAX", QVariant.Double),
			3:QgsField("YMIN", QVariant.Double), 4:QgsField("YMAX", QVariant.Double)}
			check = QFile(self.shapefileName)
			if check.exists():
				if not QgsVectorFileWriter.deleteShapeFile(self.shapefileName):
					return
			writer = QgsVectorFileWriter(self.shapefileName, self.encoding, fields, QGis.WKBPolygon, None)
			#writer = QgsVectorFileWriter(outPath, "CP1250", fields, QGis.WKBPolygon, None)
		else:
			fields = {0:QgsField("ID", QVariant.Int), 1:QgsField("COORD", QVariant.Double)}
			check = QFile(self.shapefileName)
			if check.exists():
				if not QgsVectorFileWriter.deleteShapeFile(self.shapefileName):
					return
			writer = QgsVectorFileWriter(self.shapefileName, self.encoding, fields, QGis.WKBLineString, None)
			#writer = QgsVectorFileWriter(unicode(outPath), "CP1250", fields, QGis.WKBLineString, None)
		outFeat = QgsFeature()
		outGeom = QgsGeometry()
		idVar = 0
		self.progressBar.setRange( 0, 0 )
		if not polygon:
			y = bound.yMaximum()
			while y >= bound.yMinimum():
				pt1 = QgsPoint(bound.xMinimum(), y)
				pt2 = QgsPoint(bound.xMaximum(), y)
				line = [pt1, pt2]
				outFeat.setGeometry(outGeom.fromPolyline(line))
				outFeat.addAttribute(0, QVariant(idVar))
				outFeat.addAttribute(1, QVariant(y))
				writer.addFeature(outFeat)
				y = y - yOffset
				idVar = idVar + 1
			x = bound.xMinimum()
			while x <= bound.xMaximum():
				pt1 = QgsPoint(x, bound.yMaximum())
				pt2 = QgsPoint(x, bound.yMinimum())
				line = [pt1, pt2]
				outFeat.setGeometry(outGeom.fromPolyline(line))
				outFeat.addAttribute(0, QVariant(idVar))
				outFeat.addAttribute(1, QVariant(x))
				writer.addFeature(outFeat)
				x = x + xOffset
				idVar = idVar + 1
		else:
			y = bound.yMaximum()
			while y >= bound.yMinimum():
				x = bound.xMinimum()
				while x <= bound.xMaximum():
					pt1 = QgsPoint(x, y)
					pt2 = QgsPoint(x + xOffset, y)
					pt3 = QgsPoint(x + xOffset, y - yOffset)
					pt4 = QgsPoint(x, y - yOffset)
					pt5 = QgsPoint(x, y)
					polygon = [[pt1, pt2, pt3, pt4, pt5]]
					outFeat.setGeometry(outGeom.fromPolygon(polygon))
					outFeat.addAttribute(0, QVariant(idVar))
					outFeat.addAttribute(1, QVariant(x))
					outFeat.addAttribute(2, QVariant(x + xOffset))
					outFeat.addAttribute(3, QVariant(y - yOffset))
					outFeat.addAttribute(4, QVariant(y))
					writer.addFeature(outFeat)
					idVar = idVar + 1
					x = x + xOffset
				y = y - yOffset
		self.progressBar.setRange( 0, 100 )
		del writer

	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 ) )

	def getVectorLayerByName(self, myName):
		mc = self.iface.mapCanvas()
		nLayers = mc.layerCount()
		for l in range(nLayers):
			layer = mc.layer(l)
			if unicode(layer.name()) == unicode(myName):
				vlayer = QgsVectorLayer(unicode(layer.source()),  unicode(myName),  unicode(layer.dataProvider().name()))
				if vlayer.isValid():
					return vlayer

	def getMapLayerByName(self, myName):
		mc = self.iface.mapCanvas()
		nLayers = mc.layerCount()
		for l in range(nLayers):
			layer = mc.layer(l)
			if unicode(layer.name()) == unicode(myName):
				if layer.isValid():
					return layer