Coordinate systems...

[strandwg@xxxxxxxx (Gary Strand)]

Am I the only one who gets frustrated by the way various coordinate systems are
defined and used in FERRET?

For example, plot space is defined in inches, viewports are defined in frac-
tions, and various other things can be defined in terms of inches or in the
units of the underlying data. Toss in viewports, and/or changing the window
size and the aspect ratio, and it can become very challenging. More than once 
I've had to resort to trial and error to get things in the right place, since
(at least to me) I'm not sure which units work where on the plot I'm making.

I've gone through a similar exercise with GrADS (the 'vpage' and 'parea' com-
mands could drive one crazy) but GrADS did have a couple nice transformation
functions one could use to make life a wee bit easier - one could go from
data coordinates to page coordinates and vice versa.

I guess what I'm asking for is a unified system of coordinate specification,
or a way one could specify which coordinate system one would like, that could
take into account the various manipulations of window size and aspect ratio
such that (say) a label specified like

"label 50% 50% 0 0 0.5 @AS10" 

puts a "10" exactly smack-dab in the center.

Also, to make window sizing easier, would it be possible to define window sizes
directly, in terms of (say) pixels, so that one could say:

set window/pixels/size=640x480

and get a window exactly 640 pixels by 480?

Thanks for listening to my rant(s).

--
/\        Gary Strand (303) 497-1336                                NCAR ML262A
  \_][    www.cgd.ucar.edu/ccr/strandwg                      1850 Table Mesa Dr
      \___strandwg@ucar.edu                       Boulder, Colorado, USA  80305