The University of New South Wales

School of Surveying and Spatial Information Systems


 Spatial Data Standards for the World Wide Web

by Ka Yan Elkie NG

Supervised by Mr. Adrian Hobson

Edited by J. M. Rüeger

October 2002


Geographical Information System (GIS) and Existing Web Mapping Technology

Geographical Information Systems (GIS) have been used to process and visualise spatial data for a few decades.  Today, the demand of spatial data is not coming from a small group of users, but rather from a vast variety of people from around the world.  Since the world wide web (WWW) has become one of the primary information resources, the demand for putting spatial data on the WWW has increased.  GIS developers and vendors have developed web mapping software. This option does not suit all users nor can they all afford it.  In addition, there is a lack of a standardised format in which to represent the data.  The raster graphics format, that was commonly used to represent spatial data, has limitations such as resolution and file size.  New spatial standards, using a vector graphics format, have been developed in order to suit the needs of users, because maps are naturally in vector form.  In addition, the quality of the vector graphics does not deteriorate with re-sizing, hence the accuracy of the spatial data is maintained. 

comparison between raster and vector graphics after resized

Comparison between raster bitmap graphics and vector graphics after re-sizing

 

New Spatial Data Standard - Scalable Vector Graphics (SVG)

Scalable Vector Graphics (SVG) is the newest open vector graphic standard developed by the World Wide Web Consortium and has received vast support from the computing and GIS industry.  SVG is a language that describes two-dimensional graphics, such as lines and polygons, in the Extensible Markup Language (XML).  The functionality of SVG overcomes the limitation of a conventional raster image. In addition, SVG can work in conjunction with other web programming languages such as Javascript. In order to view SVG in a browser, a plug-in (SVG Viewer) is required. (It can be downloaded from the Adobe website.)  SVG is currently a new graphic format. But it is expected that it will soon become common place and that the SVG Viewer will be included as a standard feature in future versions of web browsers.

 

GIS Web Prototype using SVG

In this project, a GIS web prototype using SVG was created based on geographic data of the University of New South Wales' Kensington Campus.  This prototype shows the power of SVG. However, it demonstrates only part of SVG functionality.  To view the prototype, the Adobe SVG Viewer is needed and one of the following hardware and software systems:

  Windows Macintosh
Operation System Windows 95, 98, SE, 2000, ME, XP, or NT 4.0 Service Pack 4 and up System 8.6 through 9.2, or 10.1 (not 10.0 through 10.0.4)
Web Browser Netscape Navigator or Communicator versions 4.0 through 4.75, or Internet Explorer 4.0 or higher. Netscape 6 is not supported. Netscape Navigator or Communicator versions 4.5 through 4.78, or Internet Explorer 5.0 or higher (un-scipted SVG only). Netscape 6 is not supported.
Hard Disk Space 13 MB of hard disk space 10 MB of hard disk space
RAM 2 MB of RAM recommended 48 MB of RAM recommended

The prototype should appear in the figure below. (Click on the image for an enlarged picture.)

To test the functionality, the prototype should be viewed in one of these two resolutions:
800x600
1024x768

Instructions on how to use the prototype can be accessed through the "Help and About" link inside the prototype or here.


For more information, please contact:

Miss Ka Yan Elkie NG
email: elkeing@yahoo.com.au

or

Mr. Adrian Hobson
email: a.hobson@student.unsw.edu.au

Mail:
School of Surveying and Spatial Information Systems
University of New South Wales
UNSW SYDNEY NSW 2052
Australia

website: http://www.gmat.unsw.edu.au

Phone: +61-2-9385-4186
Fax: +61-2-9313-7493