xgrass, multiple users and photos

Simon Cox simon at artemis.earth.monash.edu.au
Fri Dec 17 17:41:28 EST 1993

Hi Chris,

> Just getting back into the grass swing of things after
> a long lay-off! I have three questions:
> 1. Does xgrass require motif to run? or will the standard
>    X11 packaged libraries suffice?

It does not require Motif to run, but it does to compile.  I installed
the statically linked binaries of xgrass under SunOs 4.1.3 and it comes
up within openlook windows, but with a motif look and feel.  I can forward
my installation notes if you are interested.

> 2. Can I run a class of 12 on grass? We have pc xemulators
>    running in our lab and I'd like to run a grass session
>    off our sun for their practicals.

Yes - I have only had three at a time running, but the speed limiting
factor was definitely the students not the software.

> 3. i see some new air photo stuff including orthographic
>    corretion---well done! Has anyone written some code to
>    use the parallax equations to generate a DEM, if not,
>    it seems we are half way there already...any suggestions?

The main task is the correspondence problem (ie matching the
same features in the two images).  Traditionally this was
done by hand, but there are now efforts to do this automatically
- mostly very expensive.  I had a student doing this, using a technique
superior to anything else around (feature matching followed by heirarchical
pattern matching) but we stopped development when we saw Hi-View (now
available within ERMapper) and other commercial packages start to appear,
and when we saw that developing a friendly interface was definitely not
his forte ;-).  If anyone is interested we could probably make this available
for the guts of a new module.

> cheers,
> chris

You're welcome!

      __  L     Dr Simon Cox			
   ,~'  L_|\    VIEPS Department of Earth Sciences, 
,-'         \   Monash University, Clayton Vic 3168        
(            \  Australia
\    ___     /          Phone +61 3 565 5762
 L,~'   "\_x/           Fax   +61 3 565 5062
           u    simon at artemis.earth.monash.edu.au

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