1 GPLOT

GPLOT is a library of graphics routines designed to make it easier to use 
VAX GKS.  They provide routines for plot setup, drawing axes, etc. for both 
linear and logarithmic plots. It supports the drawing of data curves with 
or without markers and/or error bars on the data points.  It provides 
routines for drawing a legend which automatically reproduces the line type, 
color, and marker type used in producing each of the curves on the plot.  
There are also routines for producing contour plots, bar graphs and for 
drawing vectors with various types of arrow heads.

2 Linking to GPLOT and/or VAX GKS

 To link to the GPLOT graphics library and to the FORTRAN  binding
 version of GKS, include the following in your link statement:

	,GRAPHICS/OPT

This is only valid on node ANLPN2.  The VAXstations have run-time only 
versions of GKS so the programs must be linked on the VAX-11/750.

2 Device Nomination
It is recommended that you replace all device nomination calls with:
 
	CALL GSTART

GSTART will translate the logical names SCREEN and/or PLOTTER to determine
which device(s) to use for the plot.  If both of these logical names are 
undefined, GSTART will call GSETUP(0) to produce a menu of plot devices.  
If PLOTTER is defined as the name of a print queue to a plotter, the plot
will automatically be sent to the printer on termination.  The valid queues
for graphics are: LW, BEV, TALARIS, B223_LASER and HP.  See Output Devices
for more information about supported devices.

2 Output Devices
The following calls are available to nominate graphics devices directly:

	HP7550			(HP7550 pen plotter)
	REGIS(IDEV,ICOLR)	(VT-125/240/241)
	VT330			(VT330 monochrome terminal)
	VT340			(VT340 color terminal)
	TK4014			(Tektronix 4014 terminal emulator)
	TK4014F			(Tektronix plot file)
	LN03TK			(Tektronix plot file)
	QMS			(QMS Laser Plotter-Tektronix mode)
	TALARIS			(Talaris Laser Plotter-Tektronix mode)
	POSTSCRIPT		(POSTSCRIPT type laser printer)
	VAXSTATION		(VAXSTATION II/GPX plot)
	LA50			(LA50 plot file)

where IDEV = 1 for the VT125 and IDEV = 3 for the VT240/241, and
ICOLR = 1 for a color plot and ICORL = 0 for a black and white plot.
ICPS = 960 for 9600 baud or 120 for 1200 baud.  

2 Plot_Files

The calls TK4014F, TALARIS, LN03TK, and QMS all produce the plot file
GPLOT.TK14.  If the direct device call was used the output file must be
sent to the appropriate printer, with the correct form for putting the
printer/plotter into Tektronix mode. If the logical name PLOTTER is defined
as the name of a supported print queue, the output file will be printed
automatically on the designated printer and then the file will be deleted. 
The call HP7550 will produce the plot file GPLOT.HP7550 which must be
printed on the HP queue.  LA50 produces the plot file GPLOT.LA50, and
POSTSCRIPT produces the plot file GPLOT.PS. 

2 DISSPLA_Emulation

The following GPLOT routines are available:

ANGLE	AREA2D	BASALF	CHNDOT	COMPRS	CONNPT	CURVE	DASH	DONEPL
DOT	DUPLX	EMARK	ENDPL	EXCRV	EXYCRV	EYCRV	FRAME
GRAF	GRID	GSETUP	GXNAME	GYNAME	HEADIN	HEIGHT	HP7550	INTNO
LA50	LEGEND	LINES	LINEST	LN03TK	MARKER	MESSAG	MIXALF	MX1ALF	
MX2ALF	MX3ALF	MX4ALF	MX5ALF	MX6ALF	MYLEGN	NEWCLR	NOBRDR	PAGE
PHYSOR	PICTRC	POSTSCRIPT	QMS	REALNO	REGIS	RESET
RLINT	RLMESS	SCLPIC	SETCLR	SOLID	STRTPT	SYMORG	TALARS	THKFRM
TK4014	TK4014F	TRIPLX	VAXSTATION	XAXEND	XGRAF	XGRAXS	XINVRS
XMESS	XNAME	XPOSN	XREAL	YAXEND	YGRAXS	YINVRS	YNAME	YPOSN

Many of these routines emulate DISSPLA routines.  EXCRV, EYCRV, and
EXYCRV are like CURVE except they plot error bars. EMARK(IMARK) 
allows you to select error bars with (2) or without (1=default) 
marks on the end of the error bars.  GSETUP(1) can be called in place 
of all other device nomination calls.  Call SOLID in place of 
RESET('DOT'), etc.

2 Error_Bars

To plot y-axis error bars, call EYCRV(XARAY,YARAY,NPNTS,IMARK,ERRY), where
ERRY is the array of y-axis uncertainties.  EXCRV is similar for error bars
along the x-axis.  EXYCRV(XARAY,YARAY,NPNTS,IMARK,ERRX,ERRY) produces error
bars in both x and y directions.  By default the error bar will be a vertical
or horizontal line.  To add bars on the ends of the lines (an I mark),
CALL EMARK(2) before drawing the curve.  The other arguments for these
routines are the same as for CURVE.  (See the DISSPLA documentation).
