Program:       QPLOT

Purpose:       QPLOT plots an one dimensional slice through a set.

Category:      ANALYSIS, PROFILES, PLOTTING

File:          qplot.c

Author:        M. Vogelaar

Keywords:

   INSET=      Give set (, subset):
               Maximum number of subsets is 2048.

   FILENAME=   Write plot data to:                          [qplot.dat]
               Result table is written in Ascii in the file with this
               name. If the file already exists, the keyword OVERWRITE=
               is prompted.

   OVERWRITE=  File exists, ok to overwrite?                      [Y]/N


   STARTPOS=   Give start pos. (x1..xn):
               n is subset dimension. Start profile at this position.

   ENDPOS=     Give start pos. (y1..yn):
               n is subset dimension. End profile at this position.

   POINTS=     Number of points in plot:                           [50]
               Maximum is 8192

** XMINMAX=    Give Xmin, Xmax in plot:                    [calculated]

** YMINMAX=    Give Ymin, Ymax in plot:                    [calculated]

   CONTINUE=   C(ontinue), D(evice), Q(uit):                        [C]
               C: Continue, get nest positions.
               D: Continue but initialize plots again.
               Q: Quit program.



               Keywords to initialize plots:

** SUBDIV=     View surface subdivisions x,y:                     [1,1]
               It is possible to have more plots on the view surface.
               The number of plots can vary in both directions x and y.

   GRDEVICE=   Give graphics device to      [list of available devices]
               plot on:
               If you writing to a TEK window, open window first.

** PAPER=      Give width (cm), aspect ratio:                [0.0, 1.0]
               Change the size of the (output) view surface.
               The aspect ratio is defined as height/width.
               The default is a calculated size and aspect ratio 1.

** LINEWIDTH=  Give line width (1-21):                              [2]
               Only required if a hardcopy device is selected.



Description:   This program takes a one dimensional slice of an
               image selected by INSET=. The length and direction of
               the slice is fixed by two points given in STARTPOS=
               and ENDPOS= as X1, X2, .. Xn, and  Y1, Y2, ..Yn
               either in pixel or physical coordinates (n is the subset
               dimension). These keywords apply to all selected subsets.
               The set values at the nearest integer positions of the
               start- and endpoint will always be plotted. Interpolated
               positions will be rounded off to their nearest integer
               values. If there are pixel positions outside the subset,
               the program will warn you, but it
               will plot as long as there are pixels inside the subset.
               The number of positions to examine is specified with
               POINTS=
               Each time a plot is made, it is possible to select a
               new position until CONTINUE=Q which stops the program.
               CONTINUE=D selects a new device and reinitializes the
               plot software. SUBDIV= selects the number of plots on
               one view surface in x- and y direction. GRDEVICE=
               selects the device. The options can be obtained by
               pressing carriage return. PAPER= and LINEWIDTH= are
               important if your device is a hardcopy device.
               Plot data can be stored in a file (FILENAME=).
               Data of different plots sent to this file are separated
               by an empty line.

Updates:       Aug 19, 1991: VOG, Document created.
               Oct 10, 1991: WZ,  PGPLOT standard names implemented
               Jun, 9, 1993: VOG, Slices can contain blanks