 digitcap - digitizer capability data base.

 The 'v.digit' program has to know what and where the digitizer is on the
 system.  The describing of the digitizer is accomplished in the 
 '$(GISBASE)/etc/digitcap' file.

 In $(GISBASE)/etc there is a directory 'dig_drivers' for storing programs
 related to the digitizers.  Inside the 'dig_drivers' directory, each digitizer
 has its own directory and a 'v.digit' program.

 Example:
 For the kurta digitizer the program is $(GISBASE)/etc/dig_drivers/kurta/digit
 and for the altek the program is $(GISBSE)/etc/dig_drivers/altek/digit
 This allows for having different and multiple digitizers on the same system.


 There are four pieces of information needed for each digitizer:  name, tty,
 executable name (digit), and a description of the digitizer. 


1) name - a unique name the users can use to identify the digitizer.  This will
   be made up by you.  name should be no longer then 12 characters: 'kurta'
   This name MUST also match the name of the directory in
    $(GISBASE)/etc/dig_drivers/<digitizer>.

2) tty  -  the tty the digitizer is attached to:  '/dev/tty?'

3) executable name -  executable program name: 'digit'

4) description of digitizer - this is used to describe the digitizer to the
   user. 
		  
   Each digitizer has one line in the file.  
        Examples:
             altek:/dev/tty12:digit: Altek digitizer, backlight
             geograph:/dev/tty13:digit: Geographics digitizer 
             kurta:/dev/tty14:digit: Kurta digitizer  30 x 60 , 16 button cursor
             none:nodig:digit:  Run digit without the digitizer.


When the Gmakefile in this directory was executed it copied the 'digitcap'
file in this directory to $(GISBASE)/etc/digitcap.example .
You will have to copy $(GISBASE)/etc/digitcap.example  to 
$(GISBASE)/etc/digitcap .

    'cp  $(GISBASE)/etc/digitcap.example  $(GISBASE)/etc/digitcap'

 Now edit $(GISBASE)/etc/digitcap to make sure it is what your digitizers
 need.

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  v.digit creates a lock file in $(GISBASE)/locks with the name of the 
  digitizer.  this file remains in the directory until the session with 
  the v.digit program is finished.  This keeps other people from trying 
  to use the same digitizer.

  If v.digit exits abnormally this lock file will remain behind and keep
  anyone from using the digitizer file.

  In the rare case that v.digit does abnormally exit and it won't allow
  anyone to use the digitizer.  Remove the lock file for the digitizer in
  $(GISBASE)/locks.

