97 
VIRTUAL REALITY FOR NAVIGATION AND ANALYSIS 
OF EARTH LANDSCAPES * 
Pietro A. Brivio ', Daniele Marini 2 , Giovanna Ober 1 and Luca Solda 1 
1 Remote Sensing Dept, IRRS-CNR 
Via Ampere 56, 20131 Milan. Italy 
brivio@tel-irrs.mi.cnr.it 
2 DSI. University of Milan 
Via Comelico 39, 20135 Milan. Italy 
marini@eidomatica.dsi.unimi.it 
.ABSTRACT 
Virtual Reality is becoming a necessary methodology to exploit the use of images to improve 
human knowledge, understanding and management of complex natural systems, such as the 
earth landscape. An integrated system. TISS - Territorial Image Synthesis System, has been 
designed and implemented to reconstruct a Digital Terrain Model from sampled data, and to 
visualise the landscape, allowing an earth scientist to navigate interactively in the three 
dimensional data set, and to interrogate and examine the data. The system is a general 
purpose workbench that can be customised to user needs. In particular some modules are 
available for the measurements of DE.VI characteristics, such as slope, exposition, incoming 
radiation as a function of the elevation and other geometric and geographic characteristics. 
The use of the Virtual Reality technologies will permit the scientist to explore and simulate 
natural events as well as land use hypothesis by adopting a "what if" paradigm. 
1.0 INTRODUCTION 
Virtual Reality, which has captured the imagination of the public, refers to the interface 
methodology which allows the user to interact more naturally and directly with data through a 
computer medium (Wilson and Sclafani. 1994). 
Adopting Virtual Reality Techniques allows us to adopt a digital terrain model not only as 
the necessary structure to analyse landscape information, but also to use it as the basis of all the 
knowledge collected and created by the analysis tool, and to explore such knowledge basis 
interactively by using direct manipulation methodology. 
Recently new innovative software tools have been provided by the scientific community to 
visualise and navigate in 3d data sets, allowing us also to use three dimensional data as a new 
medium. This permits to distribute across the network 3d data as well as images, video, text and 
sound, enriching the possibilities to create user friendly tools to navigate in a knowledge basis. 
Presented at the International Society for Photogrammetry and Remote Sensing "Workshop on New 
Developments in Geographic Information Systems", Milan. Italy. 6-8 March 1996.