VIRTUAL GIS, A NEW REALITY starte 
  
appli 
By Nickolas L. Faust Georgia Tech Research Institute am 
Dharmajyoti Bhaumik Georgia Institute of Technology fligh 
Ryan Woodard Electromagnetics and Physical desig 
Dung Vu Sciences Laboratory on gi 
Atlanta, Georgia 30332 
The 
KEY WORDS: GIS, Visualization, Remote, Sensing, Geographic, Virtual Reality worl 
Computing, Rendering now 
ABSTRACT 
II. V 
The merger of Geographic Information Systems (GIS) analysis with multidimensional visualization has S 
allowed the development of a unique interactive environment for GIS systems. Instead of the traditional 
top down viewing of GIS layers and analyses using those layers, a three dimensional approach is Curr 
described that combines GIS functionality with a fast 3 dimensional code developed at the Georgia Tech view 
Research Institute (GTRI). While three dimensional perspective viewing has been common in flight spati 
simulation and has been used recently in display of remote sensing and GIS data sets, it has always been dime 
used primarily as a glitzy method to display basic data and pregenerated analyses. By combining fast be p 
rendering within a GIS structure, direct query of attributes can be added to visibility analysis allowing using 
the practical use of perspective imaging as a direct interface into a GIS analysis system. This interface and : 
is a natural method for a user to interact with spatial data sets. the s 
the @ 
from 
I. INTRODUCTION part 
posit 
Traditional methods of GIS display and A dynamic method for combining both the that 
analysis normally provide for the display of multi-layer weighting, proximity, and migl 
vector and raster GIS data in a top down, visibility operations as well as interactive be s 
seen from above presentation. Overlays, query into a single, powerful, interface whet 
proximity analyses, and other GIS analysis into GIS functionality is being developed will 
functions are always performed in a two at the Georgia Tech Research Institute anotl 
dimensional view of the database. Many of (GTRI). This should not be viewed as the Visil 
these analyses include terrain elevation data development of another new GIS system. Ways 
or derived parameters such as slope and Instead, it should be viewed as a view 
aspect. Functions such as terrain masking synergistic combination of strengths of a line 
help the user understand the influence of the rapidly expanding GIS field and the dire 
local terrain on visibility from a point within similarly expanding visualization of s 
the database. A line of sight analysis will environment. A GIS system has grown read; 
show a terrain profile between points of more and more sophisticated as new a pa 
interest in the database. Visibility is models, techniques, and applications are there 
becoming an increasingly important factor in included. Combinations of raster and that 
GIS analysis, however, a two dimensional or vector information is occurring in several alon: 
one dimensional representation of the area commercial GIS systems bring further som: 
that can be seen is not as effective as a full 3 capabilities for display and analysis of view 
dimensional view. A three dimensional spatial data. direc 
perspective view shows not only the GIS area 
layers of interest, but also what can be seen During the same time, visualization locat 
from a particular location within, above, or techniques have come out of the closet of can 
below the terrain. the computer graphics artists and have seen 
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