Cortona VRML client provides native support of GeoVRML nodes (GeoCoordinate, GeoElevationGrid, GeoLocation, GeoLOD, GeoPositionInterpolator, GeoTouchSensor, GeoViewpoint), which represent various geographic data using VRML. The support for these nodes is implemented by using native script interface. In addition, ParallelGraphics has introduced the GeoElevationGrid VRML node that uses script from the GeoElevationGrid node, but implements Cortona's SplineFaceSet extension node inside (See definition).

• How to include Cortona native support of GeoVRML nodes in your VRML scenes
• Details of native script implementation of GeoVRML nodes
• Automatic installation of Cortona GeoVRML native script library
• View a sample GeoVRML scene with Cortona native GeoVRML support
• Go to the GeoVRML Website (www.geovrml.org)

How to include Cortona native support of GeoVRML nodes in your VRML scenes

At the beginning of a VRML scene, insert the corresponding EXTERNPROTO statements for those GeoVRML nodes which are used later in this scene. For example, if you scene contains GeoLocation nodes, add the following EXTERNPROTO:

EXTERNPROTO GeoLocation [
  field	SFNode	 geoOrigin
  field	MFString geoSystem
  field	SFString geoCoords
  field	MFNode	 children
]
[ 
  "urn:web3d:geovrml:1.0/protos/GeoLocation.wrl"
  "http://www.parallelgraphics.com/vrml/proto/GeoVRML/1.0/protos/GeoLocation.wrl"
  "http://www.geovrml.org/1.0/protos/GeoLocation.wrl"
]

PROTO definitions for other GeoVRML nodes reside in the same folder at the ParallelGraphics Website, for example, for the GeoVRML_Node node, its PROTO definition has the following address:

http://www.parallelgraphics.com/vrml/proto/GeoVRML/1.0/protos/GeoVRML_Node.wrl

For the purpose of integrity, definitions of other GeoVRML nodes that do not contain Script nodes (GeoMetadata, GeoOrigin, InlineLoadControl) are also placed at ParallelGraphics Website.

Details of native script implementation of GeoVRML nodes

The code of the EXTERNPROTOs implies that for instanciating GeoVRML nodes in the VRML scenes, Cortona uses the ParallelGraphics version of the GeoVRML PROTOs (at the ParallelGraphics).

These PROTOs are declared almost identically to the original GeoVRML PROTOs, but has another values in url field of their Script nodes. For example, for the GeoLocation node:

   DEF GEOLOC_SCRIPT Script {
      ...    
      url [ 
      "nativescript: 
      libuid=Cortona.GeoVRML; 
      file-win32-x86=http://www.parallelgraphics.com/vrml/proto/GeoVRML/1.0/cortgeo.dll#1,0,0,12;
      scriptid=GeoLocation;",
     "GeoLocation.class"
	  ]
   }
}

The first value in the url field (which is a MFString list) references the appropriate native script implementation that is provided in the cortgeo.dll file.
The second value in the list ("GeoLocation.class") allows this PROTO to work under other VRML browsers that support Java and multiple url's (in case the original GeoVRML Java implementation is installed).
See full text of the GeoLocation PROTO here.
In addition, ParallelGraphics provides a set of debug version of these PROTOs (with all debug fields set to TRUE) at http://www.parallelgraphics.com/vrml/proto/GeoVRML/1.0/protos_debug/GeoLocation.wrl.

Automatic installation of Cortona GeoVRML native script library

Procedures with C++ implementation of GeoVRML nodes are included in the cortgeo.dll file (130K), which resides at the ParallelGraphics Website at www.parallelgraphics.com/vrml/proto/GeoVRML/1.0/cortgeo.dll.

This file is automatically downloaded and installed on the computer first time the user opens a GeoVRML scene in Cortona. Next times when a GeoVRML scenes will be opened in Cortona, the browser will detect that required the GeoVRML script library has been already installed and registered in the system, and therefore will use its local copy.