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GeoVRML 1.1 Specification

A. Examples

This sections contains a number of VRML examples that use the GeoVRML nodes described in the Nodes section. N.B. in order to browse these examples in a VRML browser, you will require the GeoVRML run-time to be installed on your machine. Please refer to the Sample Implementation section for details. The following table provides a summary of the examples presented below.

Example

A.1 GeoElevation example

A.2 Animated GeoViewpoint

A.3 On demand inlining

A.4 Georeferencing VRML object

A.5 Using a GeoOrigin

A.1 GeoElevation example

This example shows the use of the GeoElevationGrid and the GeoViewpoint nodes. We supply an 18 degree resolution grid of height values that are georeferenced to the latitude/longitude grid. These are then transparently transformed into a round-earth (geocentric) representation and then passed to the VRML renderer. In this example, we exaggerate the height values by a factor of 200 so that these are perceptible. Even at this coarse scale, the Himalaya are evident as a large protrusion. We specify a GeoViewpoint node to provide a good initial view of the world. It is located 10,000 km above the ellipsoid, looking directly down at the location 35 deg north by 70 deg east.

URL: http://www.geovrml.org/1.1/doc/examples/exagearth.wrl

#VRML V2.0 utf8

EXTERNPROTO GeoElevationGrid [
  exposedField SFNode   color
  exposedField SFNode   texCoord
  exposedField SFNode   normal
  field        SFBool   ccw
  field        SFBool   colorPerVertex
  field        SFFloat  creaseAngle
  field        SFNode   geoOrigin
  field        MFString geoSystem
  field        SFString geoGridOrigin
  field        MFFloat  height
  field        SFBool   normalPerVertex
  field        SFBool   solid
  field        SFInt32  xDimension
  field        SFString xSpacing
  field        SFFloat  yScale
  field        SFInt32  zDimension
  field        SFString zSpacing
] [ "urn:web3d.org:vrml97:node:GeoElevationGrid"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoElevationGrid.wrl"
    "http://www.geovrml.org/1.1/protos/GeoElevationGrid.wrl" ]

EXTERNPROTO GeoViewpoint [
  eventIn      SFBool     set_bind
  eventIn      SFString   set_position
  eventIn      SFString   set_orientation
  exposedField SFFloat    fieldOfView
  exposedField SFBool     headlight
  exposedField SFBool     jump
  exposedField MFString   navType
  field        SFString   description
  field        SFNode     geoOrigin
  field        MFString   geoSystem
  field        SFString   position
  field        SFRotation orientation
  field        SFFloat    speedFactor
  eventOut     SFTime     bindTime
  eventOut     SFBool     isBound
] [ "urn:web3d.org:vrml97:node:GeoViewpoint"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoViewpoint.wrl"
    "http://www.geovrml.org/1.1/protos/GeoViewpoint.wrl" ]

Group {
  children [

     Background {
	skyAngle [ ]
	skyColor [ 0.1 0.1 0.8 ]
     }

     GeoViewpoint {
	geoSystem [ "GD" ]
	position "35.0 70.0 30000000"
	orientation 1 0 0 -1.57
	description "Initial GeoViewpoint"
     }

     Shape {
	appearance Appearance {
	   material Material { diffuseColor 0.3 1.0 0.3 }
	}
	geometry GeoElevationGrid {
	   geoSystem [ "GD" ]
	   geoGridOrigin "-90 -180 0"
	   xDimension 21
	   zDimension 11
	   xSpacing "18"
	   zSpacing "18"
           yScale 200
           height [
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0 0 0 3135 2976 2529 2135 3449 2899 3190 2375 0
 0 3086 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 25 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 142 792 0 0 0 969 0 0 0 0 0 495 276 0
 0 0 0 0 0 0 320 46 60 0 0 0 588 0 0 0 0 0 0 34 0
 0 0 0 0 0 0 0 0 0 0 301 601 837 627 0 880 0 0 0 0 0
 0 0 0 0 202 1 0 0 0 0 1241 385 6 582 468 215 5201 529 0 0 0
 0 0 0 0 1304 427 365 374 0 0 0 1977 345 22 132 325 2072 1256 171 0 0
 0 0 706 1896 464 134 0 0 2563 0 0 0 143 11 784 88 498 307 108 1707 0
 0 0 0 0 0 0 600 378 1378 339 0 0 0 0 0 0 0 0 0 0 0
           ]
	}
     }
  ]
}

A.2 Animated GeoViewpoint

This example illustrates how to animate the camera with a GeoViewpoint node. We display a flat model of the earth using a GeoElevationGrid node and then set up a GeoPositionInterpolator to interpolate between the latitude/longitude locations for London, Paris, and New York. The output of the interpolator is routed into the GeoViewpoint and the result is an animated viewpoint that smoothly pans between all three cities.

URL: http://www.geovrml.org/1.1/doc/examples/viewanim.wrl

#VRML V2.0 utf8

EXTERNPROTO GeoViewpoint [
  eventIn      SFBool     set_bind
  eventIn      SFString   set_position
  eventIn      SFString   set_orientation
  exposedField SFFloat    fieldOfView
  exposedField SFBool     headlight
  exposedField SFBool     jump
  exposedField MFString   navType
  field        SFString   description
  field        SFNode     geoOrigin
  field        MFString   geoSystem
  field        SFString   position
  field        SFRotation orientation
  field        SFFloat    speedFactor
  eventOut     SFTime     bindTime
  eventOut     SFBool     isBound
] [ "urn:web3d.org:vrml97:node:GeoViewpoint"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoViewpoint.wrl"
    "http://www.geovrml.org/1.1/protos/GeoViewpoint.wrl" ]

EXTERNPROTO GeoPositionInterpolator [
  eventIn      SFFloat  set_fraction
  field        SFNode   geoOrigin
  field        MFString geoSystem
  field        MFFloat  key
  field        MFString keyValue
  eventOut     SFVec3f  value_changed
  eventOut     SFString geovalue_changed
] [ "urn:web3d.org:vrml97:node:GeoPositionInterpolator"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoPositionInterpolator.wrl"
    "http://www.geovrml.org/1.1/protos/GeoPositionInterpolator.wrl" ]

EXTERNPROTO GeoElevationGrid [
  exposedField SFNode   color
  exposedField SFNode   texCoord
  exposedField SFNode   normal
  field        SFBool   ccw
  field        SFBool   colorPerVertex
  field        SFFloat  creaseAngle
  field        SFNode   geoOrigin
  field        MFString geoSystem
  field        SFString geoGridOrigin
  field        MFFloat  height
  field        SFBool   normalPerVertex
  field        SFBool   solid
  field        SFInt32  xDimension
  field        SFString xSpacing
  field        SFFloat  yScale
  field        SFInt32  zDimension
  field        SFString zSpacing
] [ "urn:web3d.org:vrml97:node:GeoElevationGrid"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoElevationGrid.wrl"
    "http://www.geovrml.org/1.1/protos/GeoElevationGrid.wrl" ]

Group {
  children [
     DEF V GeoViewpoint {
	geoSystem [ "GD" ]
	orientation 1 0 0 -1.57
        position "51.5122 -0.065 10000000"
	description "Animating GeoViewpoint"
     }
     
     Shape {
	appearance Appearance {
	   material Material { diffuseColor 0.8 1.0 0.3 }
	   texture ImageTexture {
	      url "http://www.geovrml.org/1.1/doc/images/earth.jpg"
	   }
	}
	geometry GeoElevationGrid {
	   geoSystem [ "GD" ]
	   geoGridOrigin "-90 -180 0"
	   xDimension 11
	   zDimension 11
	   xSpacing "36"
	   zSpacing "18"
           creaseAngle 1.05
	   height [ 0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0
		    0 0 0 0 0 0 0 0 0 0 0 
		    0 0 0 0 0 0 0 0 0 0 0 ]
	}
     }
     
     DEF PI GeoPositionInterpolator {
	geoSystem [ "GD", "latitude_first" ]
	key [ 0.0  0.1  0.55  1.0 ]
	keyValue [ 
           "51.5122 -0.065     10000000",       # London
           "48.865   2.35      10000000",       # Paris
           "40.6698 -73.943849 10000000",       # New York
           "51.5122 -0.065     10000000",       # Back to London
        ]
     }

     DEF TS TimeSensor { 
	cycleInterval 8.0
	loop TRUE
     }
     
     Background { skyColor 1 1 1 }
  ]
}

ROUTE TS.fraction_changed TO PI.set_fraction
ROUTE PI.geovalue_changed TO V.set_position

A.3 On demand inlining

A simple example that uses the InlineLoadControl node to include a file which just contains a green cube. Click on the up arrow to send a set_load TRUE event to the InlineLoadControl node, and Click on the down arrow to send a set_load FALSE event. This examples illustrates some of the resource management features that GeoVRML 1.1 provides.

URL: http://www.geovrml.org/1.1/doc/examples/geoinline.wrl

#VRML V2.0 utf8

EXTERNPROTO InlineLoadControl [
   exposedField SFBool    load
   exposedField MFString  url
   field        SFVec3f   bboxCenter
   field        SFVec3f   bboxSize
   eventOut     MFNode    children
] [ "urn:web3d.org:vrml97:node:InlineLoadControl"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/InlineLoadControl.wrl"
    "http://www.geovrml.org/1.1/protos/InlineLoadControl.wrl" ]

Group {
   children [

      DEF TestInline InlineLoadControl {
	 url "http://www.geovrml.org/1.1/doc/examples/box.wrl"
	 load FALSE     # don't load inline file until TRUE event sent
      }

      # Two cones that are used to load and unload the URL for the box

      Transform {
	 translation 2 1.0 0 
	 scale 0.5 0.5 0.5
	 children [
	    DEF LoadSensor TouchSensor {}
	    Shape {
	       appearance Appearance { material Material {diffuseColor 1 0 0} }
	       geometry Cone {}
	    }
	 ]
      }
      Transform {
	 translation 1.5 1.2 0.3
	 scale 0.5 0.5 0.5
	 children [
	    Shape {
	       geometry Text {
		  string "Load Cube"
		  fontStyle FontStyle {
		     size 1.0
		  }
	       }
	    }
	 ]
      }

      Transform {
	 translation 2 -1.0 0 
	 scale 0.5 0.5 0.5
	 rotation 1 0 0 3.1415
	 children [
	    DEF UnLoadSensor TouchSensor {}
	    Shape {
	       appearance Appearance { material Material {diffuseColor 0 0 1} }
	       geometry Cone {} 
	    } 
	 ]
      }
      Transform {
	 translation 1.5 -1.5 0.3
	 scale 0.5 0.5 0.5
	 children [
	    Shape {
	       geometry Text {
		  string "Unload Cube"
		  fontStyle FontStyle {
		     size 1.0
		  }
	       }
	    }
	 ]
      }

   ]

}

# a couple of scripts to process the events from clicking on the cones

DEF ReturnTrue Script {
   eventIn  SFBool set_value
   eventOut SFBool value_changed
   url "javascript: function set_value( value ) { 
           if ( value == true ) value_changed = true; }"
}

DEF ReturnFalse Script {
   eventIn  SFBool set_value
   eventOut SFBool value_changed
   url "javascript: function set_value( value ) {
           if ( value == true ) value_changed = false; }"
}

ROUTE LoadSensor.isActive TO ReturnTrue.set_value
ROUTE ReturnTrue.value_changed TO TestInline.set_load

ROUTE UnLoadSensor.isActive TO ReturnFalse.set_value
ROUTE ReturnFalse.value_changed TO TestInline.set_load

A.4 Georeferencing VRML objects

This example displays a standard VRML cone at the latitude/longitude location of Lossiemouth, Scotland. The Cone is rotated through 180 deg about the X axis to point straight down rather than up. We use the GeoElevationGrid node in order to give us a (coarse) underlying reference model of the earth. We make the Cone 500 km high and 200 km above the surface of the earth so that we can see it.

URL: http://www.geovrml.org/1.1/doc/examples/geoloc.wrl

#VRML V2.0 utf8

EXTERNPROTO GeoLocation [
   exposedField SFString  geoCoords
   field        MFNode    children
   field        SFNode    geoOrigin
   field        MFString  geoSystem
] [ "urn:web3d.org:vrml97:node:GeoLocation"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoLocation.wrl"
    "http://www.geovrml.org/1.1/protos/GeoLocation.wrl" ]

EXTERNPROTO GeoElevationGrid [
  exposedField SFNode   color
  exposedField SFNode   texCoord
  exposedField SFNode   normal
  field        SFBool   ccw
  field        SFBool   colorPerVertex
  field        SFFloat  creaseAngle
  field        SFNode   geoOrigin
  field        MFString geoSystem
  field        SFString geoGridOrigin
  field        MFFloat  height
  field        SFBool   normalPerVertex
  field        SFBool   solid
  field        SFInt32  xDimension
  field        SFString xSpacing
  field        SFFloat  yScale
  field        SFInt32  zDimension
  field        SFString zSpacing
] [ "urn:web3d.org:vrml97:node:GeoElevationGrid"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoElevationGrid.wrl"
    "http://www.geovrml.org/1.1/protos/GeoElevationGrid.wrl" ]

EXTERNPROTO GeoViewpoint [
  eventIn      SFBool     set_bind
  eventIn      SFString   set_position
  eventIn      SFString   set_orientation
  exposedField SFFloat    fieldOfView
  exposedField SFBool     headlight
  exposedField SFBool     jump
  exposedField MFString   navType
  field        SFString   description
  field        SFNode     geoOrigin
  field        MFString   geoSystem
  field        SFString   position
  field        SFRotation orientation
  field        SFFloat    speedFactor
  eventOut     SFTime     bindTime
  eventOut     SFBool     isBound
] [ "urn:web3d.org:vrml97:node:GeoViewpoint"
    "file:///C:/Program%20Files/GeoVRML/1.1/protos/GeoViewpoint.wrl"
    "http://www.geovrml.org/1.1/protos/GeoViewpoint.wrl" ]

Group {
  children [

    Background { skyColor 1 1 1 }

    GeoViewpoint {
       geoSystem [ "GD", "latitude_first" ]
       position "51.5122 -40.0 10000000"
       orientation 1 0 0 -1.57
       description "Initial GeoViewpoint"
    }

    Shape {
       appearance Appearance {
	  material Material { diffuseColor 0.8 1.0 0.3 }
	  texture ImageTexture {
	     url "http://www.geovrml.org/1.1/doc/images/earth.jpg"
	  }
       }
       geometry GeoElevationGrid {
	  geoSystem [ "GD" ]
	  geoGridOrigin "-90 -180 0"
	  xDimension 11
	  zDimension 11
	  xSpacing "36"
	  zSpacing "18"
          creaseAngle 1.05
	  height [
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0
		  0 0 0 0 0 0 0 0 0 0 0 
		  0 0 0 0 0 0 0 0 0 0 0 ]
       }
    }
    
    GeoLocation {
      geoSystem [ "GD" ]
      geoCoords "57.7174 -3.286119 200000" # Lossiemouth, Scotland, elev 200km
      children [
         Transform { 
	   rotation 1 0 0 3.1415926
           children [
             Shape {
              appearance Appearance { material Material { diffuseColor 1 1 0 }}
	      geometry Cone { bottomRadius 100000 height 500000 }
	     }
	   ] 
         }
      ]
    }

  ]
}

A.5 Using a GeoOrigin

This example illustrates how to use a GeoOrigin node in order to provide accurate geospatial positioning and remove the camera jitter caused by reduced floating-point precision. We use two GeoLocation nodes to place two spheres next to each other on the surface of the earth. The spheres have radii of 2 meters and are placed 4 meters apart in an UTM spatial reference frame. We define a GeoOrigin node located between both of these spheres so that all the coordinates in the scene will lie within single-precision range. Note that all of the GeoVRML nodes in this example use the same GeoOrigin definition.

URL: http://www.geovrml.org/1.1/doc/examples/geoorigin.wrl