Version 0.1.0 of the QGIS Elevation Plugin.

AUTHORS

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+Steffen Macke <[email protected]>
+Dr. Alessandro Pasotti <[email protected]> - parts taken from GeoCoding plugin
+

Elevation.py

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+#! /usr/bin/env python
+#
+# This file is part of the QGIS Elevation Plugin
+#
+# Elevation.py - load Elevation class from file Elevation.py
+#
+# Copyright 2010 Steffen Macke <[email protected]>
+#
+# The QGIS Elevation plugin 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, or (at your option) any later version.
+#
+# The QGIS Elevation plugin 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 program; see the file COPYING. If not,
+# write to the Free Software Foundation, Inc., 59 Temple Place
+# - Suite 330, Boston, MA 02111-1307, USA.
+#
+# The QGIS Python bindings are required to run this file
+# 
+# Import the PyQt and QGIS libraries
+from PyQt4.QtCore import * 
+from PyQt4.QtGui import *
+from qgis.core import *
+
+# Standard imports. simplejson is imported later
+import sys,os,httplib, webbrowser, urllib
+sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))
+
+# GeoCoding Utils
+from Utils import *
+# Elevation imports
+import resources, numericmarkers
+
+class Elevation: 
+
+	def __init__(self, iface):
+		# Save reference to the QGIS interface
+		self.iface = iface
+		self.canvas = iface.mapCanvas()
+		# store layer id
+		self.layerid = ''
+
+	def initGui(self):  
+		self.obtainAction = QAction(QIcon(":/plugins/elevation/elevation_icon.png"), QCoreApplication.translate('Elevation', "&Obtain Elevation"), self.iface.mainWindow())       
+		self.aboutAction = QAction(QIcon(":/plugins/elevation/about_icon.png"), QCoreApplication.translate('Elevation', "&About"), self.iface.mainWindow())    
+		self.iface.addPluginToMenu("Elevation", self.obtainAction)
+		self.iface.addPluginToMenu("Elevation", self.aboutAction)
+		self.iface.addToolBarIcon(self.obtainAction)
+
+		QObject.connect(self.obtainAction, SIGNAL("triggered()"), self.obtain) 
+		QObject.connect(self.aboutAction, SIGNAL("triggered()"), self.about) 
+
+	def unload(self):
+		# Remove the plugin menu item and icon
+		self.iface.removePluginMenu("Elevation", self.obtainAction)
+		self.iface.removePluginMenu("Elevation", self.aboutAction)
+		self.iface.removeToolBarIcon(self.obtainAction)
+
+	def about(self):
+		infoString = QString(QCoreApplication.translate('Elevation', "QGIS Elevation Plugin<br />This plugin allows to mark point elevations in Google Maps.<br />Copyright (c) 2010 Steffen Macke<br /><a href=\"http://polylinie.de/elevation\">polylinie.de/elevation</a><br/>In order to use, you have to accept the <a href=\"http://code.google.com/intl/en/apis/maps/terms.html\">Google Maps APIs Terms of Service</a>\n"))
+		QMessageBox.information(self.iface.mainWindow(), "About Elevation", infoString)
+
+	# Obtain elevation
+	def obtain(self):
+		chk = self.check_settings()
+		if len(chk) :
+			QMessageBox.information(self.iface.mainWindow(), QCoreApplication.translate('Elevation', "Elevation plugin error"), chk)   
+			return                    
+		sb = self.iface.mainWindow().statusBar()
+		sb.showMessage(QCoreApplication.translate('Elevation', "Click on the map to obtain the elevation"))
+		ct = ClickTool(self.iface,  self.obtain_action);
+		self.iface.mapCanvas().setMapTool(ct)
+
+	def obtain_action(self, point) :
+		try:
+			import simplejson
+			# reverse lat/lon
+			pt = pointToWGS84(point)
+			conn = httplib.HTTPConnection("maps.google.com")
+			conn.request("GET", "/maps/api/elevation/json?locations=" + str(pt[1])+","+str(pt[0])+"&sensor=false")
+			response = conn.getresponse()
+
+			jsonresult = response.read()
+			elevation = int(round(simplejson.loads(jsonresult).get('results')[0].get('elevation')))
+			# save point
+			self.save_point(point, elevation)
+			#find marker
+			marker = 'http://bit.ly/aUwrKs'
+			for x in range(0, 1000):
+				if numericmarkers.numericmarkers.has_key(elevation+x) :
+					marker = numericmarkers.numericmarkers.get(elevation+x)
+					break
+				if numericmarkers.numericmarkers.has_key(elevation-x):
+					marker = numericmarkers.numericmarkers.get(elevation-x)
+					break
+			# create map
+			webbrowser.open('http://maps.google.com/maps/api/staticmap?size=512x512&maptype=terrain\&markers=icon:'+marker+'|'+str(pt[1])+','+str(pt[0])+'&mobile=true&sensor=false')	
+		except ImportError, e:
+			QCoreApplication.translate('Elevation', "'simplejson' module is required. Please install simplejson with 'easy_install simplejson'")
+		return 
+
+	# save point to file, point is in project's crs
+	def save_point(self, point, elevation):
+		qDebug('Saving point ' + str(point[1])  + ' ' + str(point[0]))
+		# create and add the point layer if not exists or not set
+		if not QgsMapLayerRegistry.instance().mapLayer(self.layerid) :
+			# create layer with same CRS as project
+			self.layer = QgsVectorLayer("Point", "Elevation Plugin Results", "memory")
+			self.provider = self.layer.dataProvider()
+			p = QgsProject.instance()
+			(proj4string,ok) = p.readEntry("SpatialRefSys","ProjectCRSProj4String")
+			crs = QgsCoordinateReferenceSystem()
+			crs.createFromProj4(proj4string)
+			self.layer.setCrs(crs)
+
+			# add fields
+			self.provider.addAttributes( { "elevation" : "int" } )
+
+			# Labels on
+			label = self.layer.label()
+			label.setLabelField(QgsLabel.Text, 0) 
+			self.layer.enableLabels(True)
+
+			# add layer if not already
+			QgsMapLayerRegistry.instance().addMapLayer(self.layer)
+
+			# store layer id
+			self.layerid = QgsMapLayerRegistry.instance().mapLayers().keys()[-1]
+
+		# add a feature
+		fet = QgsFeature()
+		fet.setGeometry(QgsGeometry.fromPoint(point))
+		fet.setAttributeMap( { 0 : QVariant(elevation) } )
+		self.provider.addFeatures( [ fet ] )
+
+		# update layer's extent when new features have been added
+		# because change of extent in provider is not propagated to the layer
+		self.layer.updateExtents()
+
+		self.canvas.refresh()
+
+	# check project settings before obtaining elevations
+	# return an error string
+	def check_settings (self) :
+		p = QgsProject.instance()
+		error = ''
+		(proj4string,ok) = p.readEntry("SpatialRefSys", "ProjectCRSProj4String")
+		if not ok :
+			error += unicode(QCoreApplication.translate('Elevation', "Project projection is not set: Elevation needs explicit projection set. Please set project CRS."))
+
+		try:
+			import simplejson  
+		except ImportError, e:
+			error += QCoreApplication.translate('Elevation', "'simplejson' module is required. Please install simplejson with 'easy_install simplejson'")
+
+		return error
+
+if __name__ == "__main__":
+	pass
+

README.md

@@ -1,4 +1,18 @@
-qgis-elevation
-==============
-
-Quantum GIS Elevation Plugin
+Quantum GIS Elevation plugin.
+
+The QGIS Elevation Plugin is available from http://polylinie.de/elevation
+
+Quantum GIS is available from http://www.qgis.org
+
+Functionality: The plugin will obtain and display point elevation data using 
+the Google Maps API.
+
+Use of the extension requires acceptance of the Google Maps Terms of Service:
+http://code.google.com/intl/en/apis/maps/terms.html
+
+Installation
+
+The installation can be installed using the Quantum GIS PluginInstaller from
+the "QGIS Contributed Repository".
+
+Installation from the source tarball is also possible.

TODO

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+Work with all selected records of the active layer.

Utils.py

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+"""
+***************************************************************************
+Name			 	 : Geocoding
+Description          : Geocoding and reverse Geocoding using Google
+Date                 : 28/May/09 
+copyright            : (C) 2009 by ItOpen
+email                : [email protected]
+ ***************************************************************************/
+ 
+ /***************************************************************************
+ *                                                                         *
+ *   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 qgis.core import *
+from qgis.gui import *
+
+class ClickTool(QgsMapTool):
+    def __init__(self,iface, callback):
+        QgsMapTool.__init__(self,iface.mapCanvas())
+        self.iface      = iface
+        self.callback   = callback
+        self.canvas     = iface.mapCanvas()
+        return None
+
+
+    def canvasReleaseEvent(self,e):
+        point = self.canvas.getCoordinateTransform().toMapPoint(e.pos().x(),e.pos().y())
+        self.callback(point)
+        return None
+
+
+def pointToWGS84(point):
+    p = QgsProject.instance()
+    (proj4string,ok) = p.readEntry("SpatialRefSys","ProjectCRSProj4String")
+    if not ok:
+        return point
+    t=QgsCoordinateReferenceSystem()
+    t.createFromEpsg(4326)
+    f=QgsCoordinateReferenceSystem()
+    f.createFromProj4(proj4string)
+    transformer = QgsCoordinateTransform(f,t)
+    pt = transformer.transform(point)
+    return pt
+
+def pointFromWGS84(point):
+    p = QgsProject.instance()
+    (proj4string,ok) = p.readEntry("SpatialRefSys","ProjectCRSProj4String")
+    if not ok:
+        return point
+    f=QgsCoordinateReferenceSystem()
+    f.createFromEpsg(4326)
+    t=QgsCoordinateReferenceSystem()
+    t.createFromProj4(proj4string)
+    transformer = QgsCoordinateTransform(f,t)
+    pt = transformer.transform(point)
+    return pt
+
+
+

__init__.py

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+#! /usr/bin/env python
+#
+# This file is part of the QGIS Elevation Plugin
+#
+# __init__.py - load Elevation class from file Elevation.py
+#
+# Copyright 2010 Steffen Macke <[email protected]>
+#
+# The QGIS Elevation plugin 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, or (at your option) any later version.
+#
+# The QGIS Elevation plugin 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 program; see the file COPYING. If not,
+# write to the Free Software Foundation, Inc., 59 Temple Place
+# - Suite 330, Boston, MA 02111-1307, USA.
+#
+# The QGIS Python bindings are required to run this file
+# 
+def name(): 
+	return "Elevation" 
+def description():
+	return "Obtain and display point elevation data using Google Maps"
+def version(): 
+	return "Version 0.1.0" 
+def qgisMinimumVersion():
+	return "1.0"
+def classFactory(iface): 
+	# load Elevation class from file Elevation
+	from Elevation import Elevation 
+	return Elevation(iface)