digitizers ...

[Simon Cox]

Seems like everyone gets onto similar things at the same time.
Since I recently got a CalComp digitiser going under GRASS4.1,
I will describe my experience.

I am using GRASS4.1 (still update 0 I'm afraid!) v.digit.
My platform is Sun - running SunOs 4.1.2 and 4.1.3.
The Digitiser is a CalComp Drawing Board III, which is cheaper
than the 9500 (also called the "professional?).  It has a bank of
configuration switches, which are actually spots on the tablet to
click the mouse over, and comes with a so-so manual mostly aimed at
getting people up and running on a PC running Autocad.  There are
appendices giving lots of recommended switch settings for a variety of
other PC applications, just Arc/Info and Autocad on Suns, and also
descriptions of the meanings of the switches.  It has 32 emulations
corresponding to a variety of boards, though strangely I had
to phone CalComp to find out which ones were equivalent to the
9500 that CERL had kindly supplied settings for.

Following some advice from the net, I set it up as follows:

Bank A:                 110001001101011101

Mode:           run     11
Increment:      none      00
Prompt:         off         0
data rate:      40 pps       100        (though this may be emulation specific)
resolution:     1000 lpi        110
emulation:      Hi Res binary 23   10111
Line feed:      none                    0
databits:       8                        1

Bank B:                 001100000000000001

Baud rate:      9600    001
parity:         none       100
pen drive:      low           0
commands:       use            0
ESC:            no              0
click:          no               0
pressure:       off               0
height:         off                0
tilt:           off,off             00
mouse:          no                    0
proximity       high                   0
CTS enable      on                      1

HOWEVER - recent advice from CERL suggests that in using the config file in
etc/digitizers v.digit is smart enough to set all this stuff for itself,
so it doesn't matter how you set the thing up with the puck.  I dunno
about that, so I will continue to use the settings above.

Having done that, I hooked up to ttya on a SparcStation 2 running 4.1.3,
using cc95f23_16and proceeded to have a horrible time with v.digit
catching about one cursor click in 100, performance getting noticeably
worse when the machine was busy.

I then tried the thing on ttya on the Sparcstation IPC in my office,
which runs 4.1.2, and hey-presto it works like a charm - well,
as advertised, anyway.  Nothing was changed in the digitizer
configuration or GRASS, and I have excercised the interrupt
handling by putting a big i/o hungry job running
simultaneously (a foreach loop running du) and it seems very robust.

The only thing that I can see is the different version of SunOs.
An inquiry to Sun yielded blank looks on this.  However, I'm not about
to change OS on my IPC just to satisfy my curiosity at this stage.
So I now have a happy system, but I'm not sure why it wasn't happy
before.

Just my experience ...

Simon Cox
----
___________________________________________________
      __  L     Dr Simon Cox			
   ,~'  L_|\    VIEPS Department of Earth Sciences, 
,-'         \   Monash University, Clayton Vic 3168        
(   soon     \  Australia
X<~~~~~~~~~  /          Phone +61 3 905 5762
 L,~'   "\_x/           Fax   +61 3 905 5062
           u    simon at artemis.earth.monash.edu.au
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