Re: CGM deployment?

David Crossley (davidc@erin.gov.au)
Tue, 1 Aug 1995 21:18:14 +1000


From: David Crossley <davidc@erin.gov.au>
Date: Tue, 1 Aug 1995 21:18:14 +1000
Message-Id: <199508011118.VAA23535@hades.erin.gov.au>
To: www-html@www10.w3.org
Subject: Re: CGM deployment?
Cc: geoweb@census.gov

The recent brief discussion on this list about the possibility of inline 
Computer Graphics Metafile (CGM) is of great interest to us. We in the 
geographic information community see this as a major step towards enabling 
online delivery of spatially relevant information.

As Chris Lilley <lilley@afs.mcc.ac.uk> said on 7 July, 1995:
> Inline CGM, in HTML 3.0 FIGures, would be a good enabling technology for
> large sections of the scientific and engineering Web user community.

It certainly would. We need to be able to present an interface where zoomable
maps can be used to define a geographic region of interest. We have been
developing workaround solutions to a single-click imagemap and waiting for
such a development.  

For a demonstration of one such imagemap facility please see URL:
http://www.erin.gov.au/cgi-bin/spatial_interface
Others are referenced in the associated technical information.

At the Chicago WWW conference in October, 1994 a Simple Vector Format (SVF)
was proposed to enable a map package to be delivered as a vector file for
client-side manipulation. It would permit a map to be zoomed and panned,
layers switched on or off by scale or by choice, and objects defined as
hypertext links. Discussion about SVF now seems very quiet. One suggestion
was that CGM could do the job.

Would those familiar with CGM please tell us if it is possible to define a
context sensitive region of a layer in a CGM file as a URL. If so, then this
is a real winner.

A freely available CGM viewer would be a great first step as it would allow
us to demonstrate functionality. 

I have copied this message to the "GeoWeb" list 
(http://wings.buffalo.edu/geoweb/) as an inline vector file is crucial to
current discussions.

___________________________________________________________________________
David Crossley - Geographic Information Systems Manager         GPO Box 787
email: davidc@erin.gov.au                                 Canberra ACT 2601
phone: +61 6 274 1139  fax: +61 6 274 1333                        Australia
URL:http://kaos.erin.gov.au/
ERIN          Environmental  Resources  Information  Network           ERIN
___________________________________________________________________________