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| Subject: | RE: GISList: Re: Section 508 Question - Visual disabilities and m
aps |
| Date: |
08/16/2001 03:20:20 PM |
| From: |
Ronald Cossman |
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Humm. It seems that a common thread is that maps (or Web pages or whatever)
fail to communicate when they are solely using color to convey an abstract
concept. To wit, David Irving's comments about being able to read a topo map
under nightlights make sense. You are simply trying to get from Point A to
Point B, and most topo maps, even when reproduced in a gray tone will still
convey the basic information.
Paul Henni pointed us to a get UK site about designing Web pages with the
color blind in mind. What is telling is how the functionality changes. If a
color-blind person can not see the blue highlighted text, the only visual
clue that it is a hyper-link or web address is the underline that is also
(conventionally) added. Notably we do not usually introduce a link with the
words, "What follows in a link."
Finally, to finish out this stair-step to abstraction, Jim Cueno had to
present colored zoning maps to City Council members who can not see the
colors. What they can see are the outlines of the city streets, parcels,
etc. But we rely upon color to convey abstract concepts (e.g. local zoning,
percent Hispanic, mortality rates, etc.) and a certain portion of the
population simply cannot see it. Perhaps we are venturing into the field of
symbology to suggest that maybe, for public use maps, we should consider
moving away from "abstract colors." By that I mean, what is the color of
mortality rates, or income inequality? Who the heck knows? It is not
intuitive. As long as you are mapping physical features then dirt will be
brown and water will be blue. But what about non-physical attributes?
Socially constructed indicators? Maybe parcel zoning should not be
represented by abstract colors at all (thereby avoiding the choices of
politically correct colors to represent different land uses) but instead by
symbols over a crosshatch to denote the parcel.
To illustrate the problems relative to the visualization of health data look
at:
the most excellent Dartmouth Atlas project (hyper-link to follow):
http://www.dartmouthatlas.org/
or a new set of U.S. Census maps at (hyper-link to follow):
http://www.census.gov/population/www/cen2000/atlas.html
In conclusion, our task is usually to convey information in a visual fashion
to a wide audience. Anything that makes that process more effective, which
could include reach a wider audience who cannot perceive colors, may be a
good thing. Perhaps the U.S. ADA legislation is an opportunity for us to
reexamine the widespread use and mis-use of colors in and on maps. Any
thoughts from those dealing with "abstract colors?"
Ron Cossman
MSU Social Science Research Center
Mississippi State University
-----Original Message-----
From: Henni, Paul HO [mailto:phoh@bgs.ac.uk\
Sent: Thursday, August 16, 2001 8:27 AM
To: gislist@geocomm.com
Subject: RE: GISList: Re: Section 508 Question - Visual disabilities and
m aps
Hi all - a parallel discussion has been going on on
WEB-SUPPORT@JISCMAIL.AC.UK - see below
Paul
Paul Henni
phoh@bgs.ac.uk
http://www.gsrg.nmh.ac.uk/
Earthquake and Forensic Seismology & Geomagnetism Programme, British
Geological Survey, Murchison House, West Mains Road, Edinburgh, EH9 3LA,
Scotland, UK
telephone +44 131 650 0275 [direct line\
fax +44 131 667 1877
BGS web site - http://www.bgs.ac.uk/
-----Original Message-----
From: ian.usher@HERTSCC.GOV.UK [mailto:ian.usher@HERTSCC.GOV.UK\
Sent: 15 August 2001 12:52
To: WEB-SUPPORT@JISCMAIL.AC.UK
Subject: an eye opener on accessibility
(if you'll pardon the pun)
Hello...
for anyone's info, having just started (a bit late in the redesign process
but better late than never) to consider colour-blindness issues with
respect to our colour choices for text and images, Visicheck now have a URL
engine which will simulate a given web page (not inc. CSS, Flash or certain
javascript behaviours) as seen by a 'standard' ("deuteranope") colour-blind
user. Their Photoshop plugin or downloadable Java applet simulates two
other types as well. As it's free it's definitely worth a look... compare
the evil and soon-to-be-replaced http://www.thegrid.org.uk/ with the
evil-in-a-different-way http://64.81.70.149/uploads/99787492513465/
One interesting aspect about the use of CSS from reading around the subject
is that removing underlines from links is often a good way of hiding them
from some colour blind users... I'm sure some of you know much more about
this sort of issue, but for me it's very useful.
http://vischeck.com
http://vischeck.com/vischeckURL.php3
cheers!
ian.
--
Ian Usher
Web Editor, The Hertfordshire Grid for Learning
[w\www.thegrid.org.uk
[e1\ian.usher@hertscc.gov.uk
[e2\ian_usher@yahoo.co.uk
[t\01582 830334
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