Rule the World with Tcl, Tcom and Google Earth

GS The title of this page is slightly megalomaniac ;-)

But it's just a few examples that show how to use the COM API of Google Earth with Tcl. The COM API description could be found here [L1 ].

Examples tested on console:

- Instantiating a Google Earth object:

 package require tcom
 set application [::tcom::ref createobject "GoogleEarth.ApplicationGE"]

- Query if Google Earth is initialised (1) or not (0):

 $application IsInitialized

- Get the version infos:

 set apptype [$application VersionAppType]
 set vbuild [$application VersionBuild]
 set vmajor [$application versionMajor]
 set vminor [$application versionMinor]

- Fly through a predefined route:

 # SetCameraParams <latitude> <longitude> <altitude> <altMode> <range> <tilt> <azimuth> <speed>
 #
 # <latitude>  Latitude in degrees. Between -90 and 90.
 # <longitude> Longitude in degrees. Between -180 and 180.
 # <altitude>  Altitude in meters
 # <altMode>   Altitude mode that defines altitude reference origin (1=above ground, 2=absolute)
 # <range>     Distance between focus point and camera in meters
 #             If !=0 camera will move backward from range meters along the camera axis
 # <tilt>      Tilt angle in degrees. Between 0 and 90. Looking to the horizon=90, looking to the center of Earth=0
 # <azimuth>   Azimuth angle in degrees. Looking North=0, East=90, South=180, West=270
 # <speed>     Speed factor. Must be >= 0, if >=5.0 it's the teleportation mode
 
 $application SetCameraParams 45 1 1000 1 1 60 345 1
 $application SetCameraParams 46 1 1000 1 1 60 345 1
 $application SetCameraParams 47 1 1000 1 1 60 345 1
 $application SetCameraParams 48 1 1000 1 1 60 345 1
 $application SetCameraParams 48 -4 1000 1 1 60 345 1
 $application SetCameraParams 48 -4 3000 1 1 60 300 1

- Retrieve camera infos:

 set cam [$application GetCamera 1]
 set fplat [$cam FocusPointLatitude]
 set fplong [$cam FocusPointLongitude]
 set fpalt [$cam FocusPointAltitude]
 set fpaltm [$cam FocusPointAltitudeMode]
 set range [$cam Range]
 set tilt [$cam Tilt]
 set azm  [$cam Azimuth]

- Save screenshot in black and white:

 # SaveScreenShot <file> <quality>
 # <quality> Quality factor of output image. Lowest quality is 0 and highest quality is 100. 

 $application SaveScreenShot C:/tmp/ge01.jpg 40

- Search a location:

 set sc [$application SearchController]
 $sc Search "Paris"

- Open a KML file from local filesystem and from network:

 $application OpenKmlFile C:/tmp/KML_samples.kml 1
 $application OpenKmlFile http://code.google.com/apis/kml/documentation/KML_Samples.kml 1

See also Steve Landers and David Roseman' articles at the Annual Tcl Conference 2010 : Augmented Reality, Google Earth and Tcl/Tk