GAINPLOT


GAINPLOT is a program for displaying  polynomial  gain  curves.   It  is
useful  for  checking the parameters supplied to CAL or AIPS task ANCAL.
GAINPLOT is available on both VMS and Convex-UNIX.


Example

The following example (VMS syntax) draws three gain curves:

$ GAINPLOT
PLOTFILE 'GP/ps'  NPXY=2,2

TITLE=BONN TYPE=ALTAZ 
POLY=1.0, 0.0, -0.9E-6, 0, 0, 0 
/
TITLE=HSTK TYPE=ALTAZ 
POLY=0.95029, -0.3329E-2, 0.23885E-3, -0.41802E-5, 0.24328E-7, 0 
/
TITLE=OVRO TYPE=ALTAZ
POLY= 0.956949, 2.410205E-3, -3.373362E-5, 0, 0, 0 
/
EXIT
/


Parameters

All filenames and parameters are specified in  the  usual  keyword=value
format.   To  display a picture, type a slash (/); to leave the program,
type the end-of-file character (control-Z in VMS, control-D in Unix)  or
use  the  EXIT  parameter.   Plotting  parameters  are  PLOtfile,  NPxy,
LInewidt, FONt, CHarsize, and TITle.  Other parameters are  POLY,  TYPE,
XRANGE, and YRANGE.

TYPE = "code" :  specifies  the  type  of  gain  curve  to  be  plotted.
          Specify  ALTAZ for an ALTAZ telescope (gain curve expressed as
          a polynomial in zenith angle  in  degrees)  or  EQUAT  for  an
          equatorial  telescope (gain curve expressed as a polynomial in
          hour angle in hours).  The default is "ALTAZ".

POLY = a, b, c, d, e, f (6 coefficients).  The gain curve is defined  by
          the  polynomial:  gain = a + bx + cx2 + ...  + fx5, where x is
          zenith angle in degrees or hour angle in hours.  NOTE:  if you
          don't   specify   all  the  coefficients,  the  others  remain
          unchanged  from  the  previous  plot.   It  is  advisable   to
          explicitly specify 0 for omitted terms.

XRANGE = x1,x2 :  The range of the x-axis of the plot.  The  default  is
          0.0, 90.0 for an ALTAZ gain curve, -6.0, 6.0 for an EQUAT gain
          curve.

YRANGE = j1,j2 :  The range of the y-axis of the plot.  The  default  is

GAINPLOT                                                          Page 2


          0.0,  1.5.   (Usually  gain  curves are normalized so that the
          maximum is 1.0).

PLOTFILE = "filename" :  specifies the device for graphics output, e.g.,
          '"/scr/tjp/plot"/PS'  or  "/GR" or "PLOT.LIS/VERS".  All plots
          are sent to the same device until a new value is specified for
          PLOTFILE.   If PLOTFILE is not specified, GAINPLOT will prompt
          for a device specification.

FONT = n :  specifies the font to be used for annotating the plot  (1  =
          normal, 2 = roman, 3 = italic, 4 = script); default = 1.

LINEWIDTH = n :  specifies the linewidth to be used when plotting.   The
          default (1) is recommended for most devices; 2 or 3 gives good
          results on laser printers.

CHARSIZE = x :  specifies the character size to be  used  in  annotating
          the plot, as a multiple of the default size.  The default size
          (1.0) gives characters that are about 1/40 of  the  height  of
          the plot.

TITLE = "Text" :  an arbitrary text string to be written above the  plot
          (outside the frame).  The default is "Gain Curve".

NPXY = nx, ny.  Use this parameter to plot several pictures on one page.
          nx  is the number of pictures across the width of the page, ny
          the number vertically; e.g., NPXY=2,1 to  display  two  graphs
          side-by-side.


History

Version 1.0:  1989 Feb 2 (T.J.  Pearson).