This page contains links to various new VRML97 nodes that have been developed at SRI International. These provide improved support for performing various terrain visualization related functions, such as managing deep tiled level of detail hierarchies, representing multiple terrain imageries and cultural features, georeferencing worlds using geographics coordinate systems inside VRML files, etc.This material is submitted as part of the GeoVRML Working Group effort. It is freely-available. (c) SRI International, 1999. All rights reserved.
VRML Nodes:
| GeoOrigin |
| The GeoOrigin node enables the specification of double-precision coordinates in VRML by defining an implicit local coordinate frame against which geometry is referenced. This node does nothing of itself, however it is used by many of the other GeoVRML nodes, such as GeoCoordinate or GeoElevationGrid. |
| GeoElevationGrid |
| The GeoElevationGrid node provides the same basic functionality as the built-in ElevationGrid, but offers the ability to specify coordinates in a number of geographic coordinate systems. For example, you can specify heights relative to a latitude/longitude graticule and have these transformed into a curved earth representation. |
| GeoCoordinate |
| The GeoCoordinate node provides the same basic functionality as the built-in Coordinate node, but offers the ability to specify coordinates in a number of geographic coordinate systems, in addition to VRML's Cartesian XYZ coordinate system. This provides the facility to georeference data - that is, specify its location on the Earth's surface. |
| GeoLocation |
| The GeoLocation node is implemented on the built-in Transform node. It lets you geo-reference any standard VRML model. That is, to take an ordinary VRML model and to place it at a specific location on the surface of the earth. |
| GeoPositionInterpolator |
| The GeoPositionInterpolator node provides the same basic functionality as the built-in PositionInterpolator node, but offers the ability to specify coordinates in a number of geographic coordinate systems, in addition to VRML's Cartesian XYZ coordinate system. For example, this lets you animate objects by specifing locations in terms of latitude, longitude, and elevation. |
| GeoViewpoint |
| The GeoViewpoint node provides the ability to specify a viewpoint using geographic coordinates. For example, you can set the viewpoint above a specific lat/long location and look straight down. |
| GeoMetadata |
| The GeoMetadata node provides the ability to specify metadata describing any number of GeoVRML nodes. Rather than adopt any specific metadata standard, the purpose of the GeoMetadata node is to provide links to any of these complete metadata descriptions, with the option to also supply a short, human-readable summary. |
| GeoLOD |
| The GeoLOD node provides a terrain specialised form of the VRML LOD node. It efficiently manages the loading and unloading of progressive levels of detail for a quadtree like structure. The level of detail is switched based upon the user's distance from a specified geographic location. |
| GeoInline |
| The GeoInline node provides a similar facility as the standard Inline node, except that it offers control over when the file to be inlined should be loaded, both statically (in the VRML code) and dynamically (via events passed into the node). The node also exposes all of the children nodes from the loaded scene. |
Archives:
- http://www.ai.sri.com/geovrml/1.0
- All of the above VRML nodes have been developed for the GeoVRML 1.0 release. This page is purely for test purposes and will eventually go away. The URL above is the definitive place to get the binaries and sources for these nodes.
Other Resources:
- The tsmApi Library
- This is SRI's freely-available library of functions for generating rich, multi-resolution, tiled terrain datasets that make use of the nodes presented on this page.
- The geotransform Java Package
- A Java package of routines developed by SRI International to perform fast transformations between a number of geographic coordinate systems (e.g. UTM, GCC, GDC). The algorithms used in this package are based upon those used in the SEDRIS project.
- The GeoVRML Home Page
- The GeoVRML Working Group is an official group of the Web3D (VRML) Consortium. It's goals are to develop tools and recommended practice for the representation of geographical data in ISO standard Virtual Reality Modeling Language (VRML97).