Globe Trotting with Your Data Visualizations for Google Earth

2. Globe Trotting with Your Data Visualizations for Google Earth Omar Padron

3. Outline • What is Google Earth? • KML Files • Basic Structure • Key Tags • KML Example • Strategies for Building KML Files • Loading KML Files • Other Cool Stuff

4. Globe Trotting with Your Data Visualizations for Google Earth What is Google Earth? • Software package that allows users to navigate a virtual 3D globe • Available for Windows XP, Windows Vista, Mac OS X, and Linux. • Free version limited to basic functionality (Searching, Viewing, Navigation, etc.)‏ • Can be extended through KML files. What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff

5. Globe Trotting with Your Data Visualizations for Google Earth KML FilesBasic Structure • KML (Keyhole Markup Language) is an XML schema used for representing geospatial data. • XML tags are used for representing all elements. • All locations are specified by a latitude, longitude, and altitude. • File contents follow the format shown below: What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff • <?xml version="1.0" encoding="UTF-8"?> • <kml xmlns="http://earth.google.com/kml/2.2"> • <Folder> • <name>A Folder</name> • <description>This is a folder.</description> • ... • </Folder> • </kml> • Key: • XML Header • KML Namespace Declaration • Folder Tag • Additional Content

6. Globe Trotting with Your Data Visualizations for Google Earth KML FilesKey Tags • <Folder>: Container for KML content • <Ground Overlay>: Ground Visuals • <Name> -- Name of Overlay • <name>This is a name</name> • <Description> -- Description of Overlay • <description>This is a description</description> • <Icon> -- URL to an image • <Icon> • <href>superawesomepicture.jpg</href> • </Icon> • <TimeSpan> -- Specifies when to display image • <TimeSpan> • <begin>2004-01</begin> • <end>2004-02</end> • </TimeSpan> • <LatLonBox> -- Specifies area over which to display image • <LatLonBox> • <north>90.000000000000</north> • <south>-90.000000000000</south> • <east>180.000000000000</east> • <west>-180.000000000000</west> • <rotation>0.000000000000</rotation> • </LatLonBox> What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff

7. Globe Trotting with Your Data Visualizations for Google Earth KML FilesKML Example • <?xml version="1.0" encoding="UTF-8"?> • <kml xmlns="http://earth.google.com/kml/2.2"> • <Folder> • <name>SuperMe Google Earth Lab</name> • <description>Sample file for SuperMe's Google Earth Lab</description> • <GroundOverlay> • <name>Omar Land</name> • <description>Just for fun</description> • <Icon> • <href>http://localhost/thePicture.jpg</href> • </Icon> • <TimeSpan> • <begin>2008-06</begin> • <end>2008-08</end> • </TimeSpan> • <LatLonBox> • <north>46.0166666667</north> • <south>44.6833333333</south> • <west>-70.1166666667</west> • <east>-68.1</east> • <rotation>-20</rotation> • </LatLonBox> • </GroundOverlay> • </Folder> • </kml> What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff • Key: • XML Header • KML Namespace Declaration • Folder Tag • Additional Content

8. Globe Trotting with Your Data Visualizations for Google Earth KML FilesStrategies for Building KML Files • For most scientific applications, KML files get very large very quickly. • Makes creating/editing by hand tedious and infeasible. • We can automate the creation of KML. • Question becomes: “How do we represent KML data?” • Two major approaches: • Encapsulate KML entities in data structures. • Portable • Flexible • Easy to use • Define all data within a single scope. • Less involved than writing data structures • Memory efficient • Fast What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff

9. Globe Trotting with Your Data Visualizations for Google Earth Loading KML Files • Most of the time, KML files would be written to disk with the .kml extension. • File is then opened from within Google Earth • KMZ (*.kmz) files are compressed KML files with additional meta-data attached. • KML can be pasted into Google Earth. • After loading, Google Earth can be configured to reopen files on startup. What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff

10. Globe Trotting with Your Data Visualizations for Google Earth Other Cool Stuff • KML files can use a <Link> tag to retrieve KML content from remote locations. • KML files can link to KML dynamically generated by any scripting language. • Combined, these could be used to display graphics generated on-the-fly from a remote location (like, say...a supercomputer?)‏ • KML also supports paths and three dimensional geometry, allowing for even more possibilities for data visualization. • Bidirectional communication between Google Earth clients and servers are also possible in KML, allowing for user-interaction with data. What is Google Earth? KML Files Basic Structure Key Tags KML Example Strategies for Buil... • Loading KML Files • Other Cool Stuff