Marble/Runners/DisplayGeoDataPlacemark: Difference between revisions

Revision as of 14:59, 24 May 2012

Editing Projects/Marble/MarbleCPlusPlus

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Tutorial Series	Marble C++ Tutorial
Previous	Tutorial 10 - Using the GeoPainter in order to paint GeoDataLineString objects
What's Next	Tutorial 12 - Yet missing
Further Reading	n/a

We have seen in the previous tutorials how basic geometry can be painted using the GeoPainter, now let's see how we can make it hold information too!

GeoDataPlacemark is a class which implements the features of KML's Placemark. Basically, it represents an interest point (a simple point or a more complex geometry) on the map, which has some information attached.

In order to add a GeoDataPlacemark to our widget, we will use the GeoDataDocument class, which is a container for features (including placemarks) and styles. In order to make the document visible, we need to add it to Marble's TreeModel, as shown in the example below:

#include <QtGui/QApplication>
#include <QtGui/QTreeView>

#include <marble/MarbleWidget.h>
#include <marble/GeoDataDocument.h>
#include <marble/GeoDataPlacemark.h>
#include <marble/GeoDataTreeModel.h>
#include <marble/MarbleModel.h>

#include <cstdio>
 
using namespace Marble;

  
int main(int argc, char** argv) {

	QApplication app(argc,argv);
		   
	// Create a Marble QWidget without a parent
	MarbleWidget *mapWidget = new MarbleWidget();
				    
	// Load the OpenStreetMap map
	mapWidget->setMapThemeId("earth/plain/plain.dgml");		 

	GeoDataPlacemark *place = new GeoDataPlacemark( "Marble Virtual City" );
	place->setCoordinate( 11.1, 48.41, 0.0, GeoDataCoordinates::Degree );
	place->setPopulation( 1024 );
	place->setCountryCode ( "Germany" );

	GeoDataDocument *document = new GeoDataDocument;
	document->append( place );

	// Add the document to MarbleWidget's tree model
	mapWidget->model()->treeModel()->addDocument( document );
	
	mapWidget->show();
								  
	return app.exec();
}

Copy and paste the code above into a text editor. Then save it as my_marble.cpp and compile it by entering the following command on the command line:

 g++ -I /usr/include/qt4/ -o my_marble my_marble.cpp -lmarblewidget -lQtGui -lQtCore

If things go fine, execute ./my_marble some-file.kml and you get a tree view of its structure similar to this screenshot (showing the structure of a route calculated with Marble):

Tip

Here's a little checklist to tackle some problems that might arise when compiling the code above:

You need Qt and Marble development packages (or comparable git installations), version 1.3 (Marble library 0.13), shipped post KDE 4.8
If Qt headers are not installed in /usr/include/qt4 on your system, change the path in the g++ call above accordingly.
Likewise, add -I /path/to/marble/headers if they're not to be found in /usr/include

Note

If you provide maps in your application please check the Terms of Use of the map material. The map material that is shipped with Marble is licensed in the spirit of Free Software. This usually means at least that the authors should be credited and that the license is mentioned. E.g. for OpenStreetMap the license is CC-BY-SA. Other map data shipped with Marble is either public domain or licensed in the spirit of the BSD license.