Subject: 3d rds pictures

From: [email-masked] (G.J. Flanagan)
Date: 6 Oct 92 10:48:12 GMT

Following a number of letters about our RDS images, some 
being very complimentary, and others complaining, some non
too politely about the size and bandwidth of these images
we have been doing a little research. We could be sending
more pictures, but realising the bandwidth problem and not
having a UNIX machine from which we can arrange anonymous
FTP transfers we have delayed postings. The problems we
face are as follows. 
1)Raw Postscript or UUENCODED GIF files are readable by 
  most on the net. These formats are (almost) machine
  independant, but are BIGGGGGG.
2)Archiving on UNIX compresses a typical image to 46%,
  whilst using a PC compress program (PKZIP) achives a ZIP
  file of 39% of the original. UUENCODING these increases
  the figures to 63% and 54% repectively. The original
  height information can be compressed on a similar scale 
  to 2%!!!
Now for solutions. The ideal would be machine independent
and let us simply transmit the original height files. This
raises it's own problems. New users don't have the programs
and are constantly asking for them, or totally put off by
the postings. This also applies to compressed images, given
that not all UUCODING, ziping and other compression
techniques work with all de-compressors/uudecoders etc.
Our programs are on ACORN Archimedes computers at the 
moment, so they will have to be ported to what?? UNIX, 
PC's, Macs.....? The original ideas are simple, we started
from one sentence
"Create a random dot field at the left of the picture, and
then copy this field 4 times to create the image, with
height information begin shown as a lateral shift of the 
original random dot field."
Now you can all create random dot pictures yourselves!

What do you want? 
  No futher rds pictures transmitted.
  A limited number transmitted once in a  while
  Continue with raw postscript/GIF files, or compress these
  to save 1/3 bandwidth, but add to time for everyone who
  wants to view the pictures.
  Transmit in parts, or complete images.
Please mail us with your suggestions, and we will be guided
by the majority.
Gordon Flanagan & Rob Scott
email address [email-masked]