PV~WAVE - A MAGIC TOOL!!

[Sidey Timmins]

Dear Grass-users:
                 Whilst I admire the concept of an OPEN-GIS, it really
   helps to have a reliable tool (which can be programmed) to fall back
   on. Besides, if you just want to try something new, its great to
   write a short script (called a procedure or function in WAVE), and
   run it on your data NOW, rather than waiting a year for someone to
   cast the idea in "C".

   Well what is PV~WAVE?  WAVE (PV~WAVE COMMAND LANGUAGE) is a 4th
   generation language which is interpreted and its syntax is "C"like.
   It interprets single statements and executes them write away, and
   if the result is graphic displays either on X-windows or Postscript.
   The language supports all types of variables: arrays, images, single,
   double, complex, bytes, shorts, ints, longs and strings and structures.
   The MOST REMARKABLE FEATURE of this language is that it can be
   extended by writing a procedure which is "compiled" and executed by
   a virtual machine. This means that loops and vectorized commands
   run quite fast (often as fast as compiled code and DEFINITELY
   FASTER than you can exit to the operating system to link your "C"
   or FORTRAN program FOLLOWED by execution).  Many procedures are
   supplied in source form so you can quickly alter them if you wish
   and be processing in minutes.

   What have I done with ~WAVE?  Well its pretty easy to write a
   small GIS system and its very easy to mix WAVE and compiled programs
   and the visualize the results of these programs. The exit to the
   operating system (spawn) is very simple and unlike compilcated
   systems like ARC/INFO which have to print messages etc and take
   longer. So we make beautiful maps (in B/W or color Postscript)
   and pan huge images on our X-windows screens with overlaid vectors
   x-y information and the current raster value. We also read ERDAS
   .gis files (and have no trouble swapping bytes as many poor Grassers
   find when on a different _endian machine), ARC/INFO GENERATE files,
   and we have some capability to read and edit INFO files directly.
   When someone gives me a tape or image of unkwon size, WAVE helps
   me to read the tape or image effortlessly.  Finally, we have
   tremendous success with visualization of GIS or scientific models
   and have made animations runnning on our screens.

   How do you get ~WAVE?  Call Visual Numerics, in Boulder CO at
   (303) 530-9000 and for a few dollars (MUCH LESS than ARC/INFO,
   DYNAMIC GRAPHICS etc) you can acquire a premium product with
   excellent documentation, support and uniformity to run on
   multiple platforms. My contact there is Caroline Tamers but
   the whole company has excellent people.

   In summary, A MAGIC TOOL that no GRASSHOPPER should be WITHOUT!

   Yawn...      Back to work now  and happy GIS days ahead...

       Sidey Timmins    Oak Ridge National Lab  
                        (615) 576-5546
                         stq at ornl.gov