ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS", Bangkok, May 23-25, 2001 
224 
APPLICATION OF VRML IN A DYNAMIC AND MULTI-DIMENSIONAL DIGITAL HARBOR 
Mingyang PAN 1 Yifan LI 2 Depeng ZHAO 3 
1 Nautical Science and Technology Institute of Dalian Maritime University, Dalian, China, 116026 
Tel: 86-411-4729297 E-mail: panmyfei@263.net 
2 ,3 Nautical Science and Technology Institute of Dalian Maritime University, Dalian, China, 116026 
Tel: 86-411-4729297 
Keywords: VRML, Digital Harbor, WebGIS 
ABSTRACT 
Virtual Reality Modeling Language (VRML) can create various animated and colorful three-dimensional virtual models on the Internet. 
The application of VRML in geographic information systems (GIS) provides earth scientists with a new and interactive way to model 
real-life phenomena of the geographic world. In this paper, VRML and WebGIS (geographic information systems based on web) 
technology were combined to create a dynamic and multi-dimensional digital harbor system on the Internet. The digital harbor displayed 
on browser and can be observed dynamically under any positions, any viewpoints and any zooms. Also, any geographic object in the 
digital harbor can be queried for attribute information by clicking it at the three-dimensional virtual scene or triggering directly at a query 
page. 
1. INTRODUCTION 
based on attribute are also available. 
The emergence and development of virtual reality technology 
provide earth scientists with a new and interactive way to 
analyze and model real-life phenomena of the geographic world. 
A technology combine virtual reality with GIS is developing 
rapidly. 
VRML is the most popular technology of virtual reality. It is a 
standard file format describing interactive multi-dimensional 
multimedia based Internet. VRML can create dynamic and 
colorful virtual world, which can contain sound and video, and 
whose objects can be animated and accessed interactively by 
user. A VRML file can contain other files through hyperlink, a 
series of VRML files with hierarchy relationship can create a 
limitless dynamic virtual world. The access method of VRML 
world is client/server based, VRML file and it’s supporting 
resource (such as image, video, sound etc.) are supplied by 
server, through internet the desired VRML files are downloaded 
to client and interpreted by local VRML-browser (Cosmo Player 
of SGI, Community Place of Sony, etc.) into virtual scene which 
can be browsed interactively. 
The rapid development of GIS and World Wide Web calls for the 
emerging of WebGIS. Spatial data in WebGIS site can be 
scanned with browser on the Internet, spatial query and spatial 
analysis are also available. 
2. THE ARCHITECTURE OF DIGITAL HARBOR SYSTEM 
In the digital harbor system, a three-tiers architecture of 
data-sever/apply-sever/client that often used in WebGIS is 
adopted (Fig1). 
Web Client Web Server Data Source 
Figurel .The architecture of Digital Harbor system 
The apply-server in which IIS is running act as a web-sever, and 
contain all three-dimensional spatial data stored in VRML files 
and texture images of JPGP or TIF format. In apply-server a n 
attribute query programme exploited by ASP is running for 
accessing the attribute information database through ADO 
object. 
In Data-server, SQL Server is installed to manage the attributes 
information database. The attribute information of all geo-object 
is saved in database as records. A unique ID number is used for 
linking geo-object in VRML world with its attribute information 
record in Data-server. 
Ground on the internet-based common character of WebGIS and 
VRML, we try to integrate VRML with WebGIS technology to 
design and create a Dalian digital harbor system on the Internet. 
The architecture of WebGIS is adopted in the system; 
three-dimensional spatial data are stored in VRML format file; 
and the attribute information is saved in a relational database. 
The digital harbor displayed on browser as three-dimensional 
scene and can be roamed and observed dynamically, 
bidirectional information query based on spatial feature and 
In web client, using Netscape or IE with VRML browser plug-in, 
user can browse spatial data in three-dimensional virtual scenes 
and perform bidirectional information query. 
3. IMPLEMENT THE DIGITAL HARBOR SYSTEM 
3.1 VISUALIZATION OF SPATIAL DATA 
The vector spatial information of Digital Elevation Model (DEM) 
of Dalian port area was extracted from an aerial stereograph by