pl - plot stack 1					Matthew Miller


EXAMPLES:
pl				default plot

pl vl: hst:			make histogram plot in velocity 

pl ovl:				overlay new plot on the current one.

pl d:				plot without header data if last plot
				was made with it, or with header data
				if last plot was made without it

pl agst:10,20			plot channels 10 to 20 against stack 2

pl v:100,300 h:10,20		plot with horizontal bounds from 10
				to 20 and vertical bounds from 100 to
				300

pl frh:				plot the full range of data in stack 1

rt 10;pl; rt 20; pl ovl:voff:3;rt 30; pl ovl:voff:-3
				plot stacks 20 and 30 over stack 10
				with a vertical offsets of 3 and -3,
				respectively, in the current plot units.  
				The offset can be positive or negative 
				and reverts to zero if not specified.  
				This option is useful for comparing
				overlaid spectra without having them
				right on top of each other. Use of
				voff will not change the plot's
				vertical range.

pl hst: lt:1			make a histogram plot with dotted lines

pl tk:				plot with ticks instead of grid

pl mlb:"MOON"			make a plot with the title "MOON"

gt 84b1000 exp:;pl vl:;gt nbe:;pl ovl:hst:
				plot the expanded spectrum and then overlay
				it with a histogram of the narrow backend

DESCRIPTION:
Pl makes a graph of the data in stack 1.  The graph is made up of five parts,
four of which may be turned on or off.  The part which may not be turned off
is the data part.  The other four parts are the grid, labels, header data, and
use array.  Each of these may be toggled on or off for all following plots by
typing the label associated with it.  All the parts start on.  The five parts
are described below.

Data:

This contains the actual graph of the data in stack 1.  It consists of a bor-
der, the graph itself, and overflow and underflow marks.

The border is just a box surrounding the graph.

By default, the graph is of temperature (vertical axis) against channel
(horizontal axis), but the graph may be made of the stack 1 temperatures
against the stack 2 temperatures.  This is described later.

The graph may be made with simple lines connecting the points (default),
symbols marking the points, or lines going halfway over, all the way up or
down, and halfway over to form a histogram.  These are selected with the
flags 'lin', 'ps', and 'hst' respectively.  The lines used for the 'lin'
and 'hst' modes may be any one of three types.  By default they are type
9 which is a narrow or black solid line.  See the documentation for fl
for a discussion of line types. See 'gm ?!' for a discussion of
symbol types.

The graph is bounded by the horizontal bounds (from 'f' to 't') and the
vertical bounds (from 'f' to 't').  The horizontal is given in the current
plot units (see description of labels).  If the channel represented by the
horizontal from is greater than the channel represented by the horizontal
to, then the graph is made backwards.  If the horizontal from is not given,
then it will default to its previous value (compensating for a change in
plot units) unless the commands gt or rt have been executed since the last
plot, in which case it defaults to the value representing channel 0.  The
horizontal to defaults to its previous value (compensating for a change in
plot units) unless one of the commands gt and rt has been executed since
the last plot, in which case it defaults to the value representing the last
channel in stack 1.  The horizontal bounds may be forced to their previous
values (not compensating for a change in plot units) with the flag 'oh'.
They may be forced to the values representing channel 0 and the last channel
in stack 1 with the flag 'fhr'.

The vertical is given in degrees K.  If the vertical from is greater than
the vertical to, the graph will be made upside down.  If the vertical from
or the vertical to is missing, it will default to a reasonable value given
the data in stack 1.  The vertical bounds may be forced to their previous
values with the flag 'ov'.


If a given channel that is plotted is outside of the vertical limits, then
an overflow or underflow mark is placed at that channel.  These appear as
short lines just above or below the border at the place where the graph is
out of bounds.

New data may be overlaid on the current plot with the flag 'ovl'.  If this
is used then the entire previous plot is kept and just the graph and the
overflow and underflow markers are plotted for the new one.  Note: you may
specify a new horizontal range for the overlay, but the data within that
range will only be plotted if it fits on the previous plot (matching
horizontal plot units).

Grid:

The grid part of the plot is the grid of lines or ticks marking the locations
of a number of equally spaced values on the horizontal and vertical axis.
The grid may be turned on and off with the flag 'g'.

By default the grid is a grid of line type 0 (line type 2 for lines that
mark the location of 0), but the label 'tk' may be used to change that to
ticks.

The spacing of the lines or ticks is defined by the horizontal and vertical
steps ('s').  The horizontal step is given in the current plot units, and
the vertical step is given in degrees K.  The default values for the
horizontal and vertical steps are chosen to make around 8 divisions.  If
'oh' is used then the horizontal step has its previous value.  Likewise,
if 'ov' is used then the vertical step has its previous value.  The lines
and ticks will be located in such a way that they represent even multiples
of the step size.

Label:

The label part of the plot consists of the horizontal label, the vertical
label, and the numbering on the grid.  It can be turned on and off with
the flag 'l'.

The horizontal, vertical, and main labels can be entered in 'hlb', 'vlb',
and 'mlb', respectively.  The actual location of these labels on the plot
is terminal dependent, but, in general, the horizontal label is just below
the graph, the vertical label is on the left hand side, and the main label
is on top in large letters.

If the horizontal label is not given, it will default to one of the following
values:
	"Channels"
	"Velocity(K)"
	"Frequency(Mhz)"
	"Antenna Temp.(K)"
depending on the current plot units.

If the vertical label is not given, it will default to "Antenna temp.(K)".

The main label does not yet have any default values.

The numbering on the grid gives the value each line or tick on the grid
represents.  The horizontal numbering is in the current plot units, and
the vertical numbering is in degrees K.

The current horizontal plot unit may be changed to channel, frequency,
or velocity for all subsequent plots with the flags 'ch', 'fr', and
'vl', respectively.

Header data:

Some of the stack 1 header information is printed in a format that is
terminal dependent.  If stack 1 is the result of a recent gt, some scan
header information will be printed also.  Header printing may be
turned on and off with the flag 'd'.

Use array:

The use array is plotted as a line between the underflow markers and the
horizontal numbering.  Where the use array is not set, the line is broken.

The use array may be turned on and off with the flag 'u'.

Plotting against stack 2:

If the 'agst' flag is used, then the horizontal axis represents the
temperature of stack 2.  Each channel from 'f' to 't' for which the use
array is on is plotted at the intersection of the temperatures for it
in stacks 1 and 2.

The use array is not plotted regardless of whether it is on or off as it
would be meaningless.

The horizontal bounds default in the same way as the vertical bounds, and
the horizontal label defaults to "Stack 2 Antenna Temp.(K)" The current
plot unit is considered to be degrees K.  Where input in the current plot
unit is to be translated into channels, no change in value will occur.
Thus 35 degrees K translates to channel 35.

This document was last updated on Tue Oct 17 16:24:05 EDT 2000 by Marc W. Pound.