.ec _
.ll 76
.ad b
.in 4
.\"====================================================================
.ti -4
1 Language
.ce
GREG1_\ Language Summary

.nf
AXIS      : Draws an axis according to its name
BOX       : Makes a box labelled according to LIMITS and TICKSPACE
COLUMN    : Reads the data file
CONNECT   : Connects (X,Y) pairs with line segments
CORNERS   : Display corners of the plotting surface.
CURVE     : Connects (X,Y) pairs with a spline interpolation
DRAW      : Calls the interactive cursor or execute detailed command
ERRORBAR  : Draws error bars on (X,Y) pairs
HISTOGRAM : Connects (X,Y) pairs as an histogram
LABEL     : Writes a string... according to options given
LIMITS    : Sets the limits of the plot (no args for auto)
LOOK      : Calls the cursor and executes a command when pressing key
PENCIL    : Selects and defines the pen attributes
POINTS    : Draws markers at the (X,Y) pairs
RULE      : Makes a grid by joining axis tickmarks
SET       : Modifies some basic parameters
SHOW      : Shows basic parameters
TICKSPACE : Sets tick intervals for BOX or AXIS
VALUES    : Write the Y or Z values at the (X,Y) positions
.fi
.\"====================================================================
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1 AXIS
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[GREG1_\]AXIS NAME [A1 A2] [/TICK Orien Small Big] [/LOCATION X Y Len]
[/LABEL Code [ONLY]] [/[NO]LOG] [/ABSOLUTE] [/UNIT Valid__Unit]
[/[NO]BRIEF]

Makes an axis labelled from A1 to A2 at location X, Y, length Len. The
current ORIENTATION determines the angle of the axis.

The axis scale is LINEAR or LOGARITHMIC according to the option
/[NO]LOG.

/TICK: the tick orientation "Orien" may be IN or OUT or NONE with
respect to the BOX. Tick spacing can be defined by Small and Big (see
HELP TICKSPACE for more information on the tick spacing on linear and
logarihmic axes). The orientation NONE cancels both ticks and labels.

/LABEL: labels for other "Orien" are drawn according to the code
N[one], P[arallel] or O[rthogonal] (to the axis). If option /LABEL has
the second argument ONLY, only the labels of the axis are written, not
the axis nor the ticks. This feature allows use of different pens for
the labels and the axis.

AXIS provides default values for all these parameters according to the
axis NAME (XLow, XUp, YLeft, YRight) and the current values used by
BOX.

AXIS creates a graphic segment named "AXIS".
.\"--------------------------------------------------------------------
.ti -4
2 /ABSOLUTE

The option /ABSOLUTE is used to write (RA,DEC) labels for EQUATORIAL
system or (L,B) coordinates for GALACTIC system when a projection is
active, i.e., both a PROJECTION and a SYSTEM are defined. RA (or L)
is used for X-like axis, and DEC (or B) for Y-like axis. Note that
this should be used only for small fields (size less than 0.2
Radians), and must be used only with the axes at the default position
(i.e. no /LOCATION option). When SYSTEM is defined but the projection
is NONE or has never been defined, the /ABSOLUTE option supports large
fields (since PROJECTION_ NONE makes a non-conformal mapping
anyway). The SET_ SEXAGESIMAL command (see help) permits some
mastering on how UNKNOWN or GALACTIC ABSOLUTE labels are written.

See HELP_ TICKSPACE for more information on how to master the Tick
spacing with the /ABSOLUTE or the /UNIT options.
.\"--------------------------------------------------------------------
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2 /BRIEF

The options /BRIEF and /NOBRIEF can be used to override the default
tick labeling as ruled by the command G_\SET AXIS. If /BRIEF is used,
the tick labels are abbreviated, if possible. If /NOBRIEF is present,
the tick labels are kept entire. The 2 options are exclusive. See HELP
G_\SET AXIS for details and examples.
.\"--------------------------------------------------------------------
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2 /LOCATION
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[GREG1_\]AXIS NAME /LOCATION X Y Len

By default, each axis (XLow, XUp, YLeft, YRight) is drawn by
connecting the appropriate corners of the current box location. For
example, XLow draws an axis from [BOX__XMIN,BOX__YMIN] to
[BOX__XMAX,BOX__YMIN]. This can be overriden with the option /LOCATION
by giving custom starting point and axis length (in paper
coordinates).
.\"--------------------------------------------------------------------
.ti -4
2 /UNIT

The option /UNIT is used to convert the axis coordinates to the
desired unit, M for arc minutes, S for arc seconds, R for
Radians. This option is valid only if a PROJECTION and a SYSTEM
(EQUATORIAL or GALACTIC) are both defined. See HELP_ TICKSPACE for
more information on how to master the Tick spacing with the /ABSOLUTE
or the /UNIT options.
.\"====================================================================
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1 BOX
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[GREG1_\]BOX [Arg1 [Arg2 [Arg3]]] [/ABSOLUTE] [/UNIT valid__unit]
[/LABEL Pen] [/FILL Color] [/[NO]BRIEF [X|Y]]

BOX puts axes around the plot region, labelling the lower and left
ones. Arguments can be used to customize the ticks and labels:
.in +4
.ti -4
-_ Arg1, Arg2: modify the labelling of the lower and left axes
respectively. They may take the values P for Parallel labels (default
for X axis), O for Orthogonal labels (default for Y axis) or N for No
labels (preserving the ticks).
.ti -4
-_ Arg3: indicates that the ticks are to be IN or OUT of the box, or
not drawn at all (NONE). Disabling ticks also disable labels.
.in -4

The option /LABEL is used to specify a different pen to use for axis
labelling. Creates a supplementary graphic segment "LABEL".

The option "/FILL Color" will fill the inside of the box with the
specified color (see HELP PEN /COL for possibilities). Creates a
supplementary graphic segment "BACK".

BOX_ N_ N_ N makes a rectangle with the current pen, even if the pen is
dashed.
.\"--------------------------------------------------------------------
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2 /ABSOLUTE
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The option /ABSOLUTE is used to write (RA,DEC) labels for EQUATORIAL
system or (L,B) coordinates for GALACTIC system when a projection is
active, i.e., both a PROJECTION and a SYSTEM are defined.  RA (or L)
is used for X-like axis, and DEC (or B) for Y-like axis. Note that
this should be used only for small fields (size less than 0.2
Radians), and must be used only with the axes at the default position
(i.e. no /LOCATION option). When SYSTEM is defined but the projection
is NONE or has never been defined, the /ABSOLUTE option supports large
fields (since PROJECTION NONE makes a non-conformal mapping
anyway). The SET_ SEXAGESIMAL command (see help) permits some mastering
on how UNKNOWN or GALACTIC ABSOLUTE labels are written.

See HELP TICKSPACE for more information on how to master the Tick
spacing with the /ABSOLUTE or the /UNIT options.
.\"--------------------------------------------------------------------
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2 /BRIEF
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The options /BRIEF and /NOBRIEF can be used to override the default
tick labeling as ruled by the command G_\SET AXIS. If /BRIEF is used,
the tick labels are abbreviated, if possible. If /NOBRIEF is present,
the tick labels are kept entire.

If the keyword X or Y is used as argument of the options, it indicates
to apply the corresponding mode only to the designated axis.

The options /BRIEF and /NOBRIEF are compatible as long as the same
axis is not designated twice. See HELP G_\SET AXIS for details and
examples.
.\"--------------------------------------------------------------------
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2 /UNIT
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The option /UNIT is used to convert the axis coordinates to the
desired unit, M for arc minutes, S for arc seconds, R for
Radians. This option is valid only if a PROJECTION and a SYSTEM
(EQUATORIAL or GALACTIC) are both defined. See HELP_ TICKSPACE for
more information on how to master the Tick spacing with the /ABSOLUTE
or the /UNIT options.
.\"====================================================================
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1 COLUMN
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[GREG1_\]COLUMN [X Nx] [Y Ny] [Z Nz] [/FILE Name] [/LINES L1 [L2]]
[/COMMENT "Separator"]
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[GREG1_\]COLUMN [X Nx] [Y Ny] [Z Nz] [/TABLE Name] [/LINES L1 [L2]]
[/CLOSE]

This command will read X data from column Nx of the current file, Y
data from column Ny and Z data from column Nz of the current (or
specified) input file or binary table. Any combination of any of three
X,Y,Z items is valid in any order, provided the column number
immediately follows the column descriptor. The X and Y arrays contain
respectively the X and Y coordinates of points to be plotted. The Z
array is an additional buffer which is used for ERRORBARS, for RANDOM
maps and so on.
.\"--------------------------------------------------------------------
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2 /COMMENT
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[GREG1_\]COLUMN /COMMENT "Separator"

Specify which character is used to indicate the beginning of a comment
line in the input file. "Separator" is a single character; typical
values are "!", ";", "#", although any single character can be
specified. The default is set by command SET_ COMMENT (default "!").
.\"--------------------------------------------------------------------
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2 /CLOSE
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[GREG1_\]COLUMN /CLOSE

Free memory allocated for the table previously opened with command
COLUMN_ /TABLE, if any.

Formatted files opened with COLUMN_ /FILE are implicitly closed right
after read: this option is useless in this case.
.\"--------------------------------------------------------------------
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2 /FILE
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[GREG1_\]COLUMN /FILE File__Name

Indicates in which formatted (list-directed free format) file the data
are to be read. If not given, the last input file is used.

Use wisely this command on extremely large formatted file because the
memory allocated by the COLUMN command is never released before
program exit.
.\"--------------------------------------------------------------------
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2 /LINES
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[GREG1_\]COLUMN /LINES L1 [L2]

Limit the range of lines read in the input file or table. L1 and L2
refer to absolute line numbers. Since comment lines are ignored,
number of read lines is at most L2-L1+1, and can be 0 if all lines
were comments.

This option is useful to avoid non-data lines, or to read by pieces a
formatted file which is too long for the column buffers. L1 and L2 are
reinitialized for each new input file or table. L2 defaults to end of
file if not specified.
.\"--------------------------------------------------------------------
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2 /TABLE
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[GREG1_\]COLUMN /TABLE Table__Name

Indicates that the columns are to be read in a "Table" at the GILDAS
format. If not given, the last input table is used. "Table" format is
typically 100 times more efficient used than the formatted file
format.
.\"====================================================================
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1 CONNECT
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[GREG1_\]CONNECT [Array__X Array__Y] [/BLANKING Bval Eval] [/FILL
[Color]]

CONNECT draws line segments connecting the coordinates read by COLUMN
X and Y, or stored in the variables Array__X Array__Y. The current
pencil with its dashed pattern is used.

CONNECT uses the current blanking values, which can be overridden by
the /BLANKING option. Hence, it does not connect with data points so
that abs(Y(i)-Bval)_ <=_ Eval. Eval negative means no blanking value,
and Bval and Eval values default to those specified in SET_ BLANKING.
.\"--------------------------------------------------------------------
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2 /FILL
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[GREG1_\]CONNECT [Array__X Array__Y] /FILL [Color]

The /FILL option indicates to fill the connected line. Blanking is
irrelevant. The connected line is closed by linking together the first
and last point. It is then filled with the color of the current pen,
or with the specified color if any (see HELP PEN /COL for
possibilities).
.\"====================================================================
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1 CORNERS
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[GREG1_\]CORNERS
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Displays angles in corners indicating the limits of the plotting
surface.
.\"====================================================================
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1 CURVE
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[GREG1_\]CURVE [Array__X Array__Y] [/ACCURACY A] [/VARIABLE V
[Array__V]] [/PERIODIC] [/BLANKING Bval Eval]

Builds the spline interpolation of the (X,Y) pairs read by COLUMN, or
stored in the variables Array__X Array__Y, using the selected
algorithm and options. The current pen with its dashed pattern is
used. Presently the only algorithm available is CUBIC__SPLINE. By
default, the command assumes that a curve Y=f(X) is to be plotted ;
this can be changed using options to specify the kind of curve to be
plotted.
.\"--------------------------------------------------------------------
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2 /ACCURACY
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  [GREG1_\]CURVE /ACCURACY A

Controls the accuracy of the spline interpolation. The argument is the
desired accuracy (in paper units, i.e. centimeters) and should be set
to the plotter resolution. The default value is defined using the
SET_ ACCURACY command.
.\"--------------------------------------------------------------------
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2 /BLANKING
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[GREG1_\]CURVE /BLANKING Bval Eval

Does not uses data points such that abs(Y(i)-Bval)_ <_ Eval. These
points act as separators. Eval negative means no blanking value. Bval
and Eval values default to those specified in SET_ BLANKING.
.\"--------------------------------------------------------------------
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2 /PERIODIC
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[GREG1_\]CURVE /PERIODIC

Specifies that the curve is periodic (and currently closed also). If
/VARIABLE_ X, it expects that y(1)=y(NXY)_ ; if /VARIABLE_ Y, that
x(1)=x(NXY)_ ; and in the case of a parametric curve, that x(1)=x(NXY)
and y(1)=y(NXY).
.\"--------------------------------------------------------------------
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2 /VARIABLE
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  [GREG1_\]CURVE /VARIABLE V [Array__V]

Selects the the interpolation variable V, which may be
.in +4
.ti -2
-_ X_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ To plot a function Y=F(X) (Default)
.ti -2
-_ Y_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ To plot a function X=F(Y)
.ti -2
-_ Z_ [Array__V]_ _ _ _ _ _ _ _ _ To plot a curve with an explicit
parametrization using the Z array, or the array Array__V if this
second argument is present.
.ti -2
-_ POLYGONAL__LENGTH_ _ _ _ To plot a curve using the polygonal length
of the curve as parametrization. It is fast and of general use.
.ti -2
-_ CURVILINEAR__LENGTH_ _ Refined and slow version of the
parametrization in POLYGONAL__LENGTH.
.ti -2
-_ NUMBERING_ _ _ _ _ _ _ _ _ _ _ The parameter is the numbering of
points.  It is only appropriate if the numbering reflects a reasonable
parametrization of the curve.
.in -4
.\"====================================================================
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1 DRAW
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[GREG1_\]DRAW Argument Xc Yc [/CLIP] [/BOX N] [/CHARACTER N] [/USER
[Unit]]

This is a powerful command which allows you to make drawings without
data either by specifying coordinates (Xc,Yc) and action desired
(Argument), or by interactive use of a cursor.

The cursor is obtained in the current active window if Xc and Yc are
omitted, and the appropriate action is then specified by keys typed at
the keyboard: R is for RELOCATE, L for LINE, M for MARKER, A for
ARROW, T for TEXT. In addition, C works like T, but prompts for the
centering parameter in addition to the text. D can be used to DELETE
the last operation, and has no action on the operations which were
plotted previously to the current DRAW command. E exits from the
cursor routine. ^C will exit AND generate an error, which can be
trapped (useful to regain control inside of forever SIC loops calling
the interactive cursor repeatedly).

Other keys gives you the cursor coordinates (in the current angular
unit when a projection is defined), except that keys `0' `1' `2' and
`3' temporarily (i.e., as long one does not exit from cursor mode)
change the current angular unit in which the cursor coordinates are
returned.

For graphical displays, you may use the mouse buttons for the commands
R (left mouse button), L (middle mouse button), and E (right mouse
button).

The complete command is written to the LOG__FILE so that you can
replay it easily. The option allows you to supersede the default value
of the coordinate system defined by SET_ COORDINATE or to keep
clipping.

When using the explicit form, Xc and Yc may be equal to * to use the
current pen position.

Any "realistic" combination of literal values, 0-d and 1-dimensional
variables is accepted for that command. For example,
.nf
  DRAW MARKER A B /USER MINUTES
.fi
will plot markers at each location given by the two arrays A and B
(provided they are of the same size). A and B must be CHARACTER arrays
in the case where the "/USER_ ABSOLUTE" option is used.
.\"--------------------------------------------------------------------
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2 ARROW
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[GREG1_\]DRAW ARROW Xc Yc

Draw an arrow from current location to given location. The arrow size
is governed by EXPAND and MARKER size. Cursor form A.

See also command G\ARROW.
.\"--------------------------------------------------------------------
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2 LINE
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[GREG1_\]DRAW LINE Xc Yc

Move pen down to given location (Xc,Yc). The line will be clipped in
the box only if the /CLIP option is present. Cursor form L.
.\"--------------------------------------------------------------------
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2 MARKER
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[GREG1_\]DRAW MARKER Xc Yc

Draw a graphic marker at given location (Xc,Yc). Current marker style
and size is used. Cursor form M.
.\"--------------------------------------------------------------------
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2 RELOCATE
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[GREG1_\]DRAW RELOCATE Xc Yc

Move pen up to given location (Xc,Yc). Cursor form R.
.\"--------------------------------------------------------------------
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2 TEXT
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[GREG1_\]DRAW TEXT Xc Yc "Text" [N [Orien]] [/CLIP [SOFT|HARD]]

Draw a text at location (Xc,Yc) according to the centering parameter
N, or to the current centering parameter if N is not specified. Cursor
form T, or C to be prompted for the centering.  The orientation angle
of the text (in degrees, counterclockwise) can be specified after the
centering parameter; otherwise the current orientation defined by
SET_ ORIENTATION is used.

The text can be clipped at the box boundaries with the option /CLIP. 2
modes are available:
.in +4
.ti -2
-_ SOFT truncates the text symbols exactly at the box boundary, which
means some part of the text will disappear.
.ti -2
-_ HARD clips everything or nothing. If the reference point (Xc,Yc) is
in the box, all the text is drawn (even if some parts are partly out
of the box). If the reference point is out of the box, the text is not
drawn at all (even if some parts are partly in the box).
.in -4
If the clipping mode is omitted, the default is SOFT.
.\"--------------------------------------------------------------------
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2 VALUE
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[GREG1_\]DRAW VALUE Xc Yc

Inquires the map value at the location (Xc,Yc). A regular grid array
must be present to use this, (Xc,Yc) must be within the Regular Grid
array limits; otherwise the command is ignored. Cursor form V.
.\"--------------------------------------------------------------------
.ti -4
2 /BOX
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[GREG1_\]DRAW [Action Xc Yc] /BOX N

Specifies that coordinates Xc Yc are physical units relative to point
number N of the current BOX. The 9 most remarkable points of the box
(corners, middle of the sides, and box center) are numbered according
to a VT100 numeric keypad notation (see
HELP_ GREG1_\LABEL_ /CENTERING ).
.\"--------------------------------------------------------------------
.ti -4
2 /CHARACTER
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[GREG1_\]DRAW [Action Xc Yc] /CHARACTER N

Specifies that coordinates Xc Yc are units of character size, and
relative to point number N of the current BOX. The 9 most remarkable
points of the box (corners, middle of the sides, and box center) are
numbered according to a VT100 numeric keypad notation (see
HELP_ GREG1_\LABEL_ /CENTERING ).
.\"--------------------------------------------------------------------
.ti -4
2 /CLIP
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[GREG1_\]DRAW [Action Xc Yc] /CLIP

Keeps clipping in the box for all drawing actions (except for labels
which are never clipped).
.\"--------------------------------------------------------------------
.ti -4
2 /USER
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[GREG1_\]DRAW [Action Xc Yc] /USER [Unit]

Specifies that coordinates are user coordinates.

The Unit argument in the /USER option, if present, can be any of
SECONDS, MINUTES, DEGREES, RADIANS (in which case the Xc and Yc
coordinates are taken to be in the corresponding unit) or ABSOLUTE (in
which case Xc and Yc are taken as absolute coordinates, usually
exprimed in sexagesimal format). The presence of the code suboption is
valid only if a PROJECTION and a SYSTEM (EQUATORIAL or GALACTIC) are
both defined.
.\"====================================================================
.ti -4
1 ERRORBAR
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[GREG1_\]ERRORBAR Argument [Array__X Array__Y Array__Z [Orientation]]

This command draws error bars on all (X,Y) points (read by COLUMN_ X
and Y, or specified in Array__X Array__Y) of length read by COLUMN_ Z
or specified by Array__Z.  Argument may be +X X -X +Y Y or -Y.
Symmetric errorbars are drawn if you do not specify the sign, while
only the errorbar of the given sign is drawn if you do so. This allows
independent errorbars in opposite directions. The size of the line at
the end of the errorbar is the Marker size and can therefore be
adjusted with SET_ MARKER.

Errorbars with arbitrary orientation can be obtained by specifying
code +O, O or -O. The orientation (in degrees) is then either read
from a fourth array if one is specified on the command line, or
otherwise taken from the current marker orientation (as specified in
SET_ ORIENTATION).
.\"====================================================================
.ti -4
1 HISTOGRAM
.ti +4
[GREG1_\]HISTOGRAM [Array__X Array__Y] [/BASE [Ybase]] [/BLANKING Bval
Eval] [/FILL [Colour]] [/HATCH [Ipen] [Angle] [Separ] [Phase]] [/Y]

Connect the coordinates read by COLUMN_ X and Y, or stored in the
variables Array__X Array__Y as a histogram.

The /BASE option specifies a "true" histogram, connected to a base
level. A scalar value means a flat base level, while a 1D variable
(same size as X and Y arrays) means a custom base for each
bin. Default is 0 base level.

The /BLANKING option will supersede the current blanking values (as
defined by SET_ BLANKING command) so that data points with
abs(Y(i)-Bval)_ <_ Eval are not plotted. Eval negative means no
blanking value. Blanking always applies on bin counts, i.e. Array__Y
values, or Array__X values if /Y is present.

By default, binning is done along X axis (assuming increasing Array__X
values), and Array__Y provides the bin counts. This can be reverted
thanks to option /Y. In this case, binning is one along Y axis
(assuming increasing Array__Y values), and Array__X provides the bin
counts. This creates a 90 degrees rotated histogram.
.\"--------------------------------------------------------------------
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2 /FILL
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[GREG1_\]HISTOGRAM [Array__X Array__Y] /FILL [Colour] [/BASE Ybase] 

The /FILL option indicates to fill the histogram with the current pen
colour or with the specified colour (see HELP PEN /COL for
possibilities). Blanking is handled as for other histograms. Usually
needs to be done in conjunction with the /BASE option to properly fill
the histogram. Icol is the number (0-23) of the color used to
fill. The colors of the last 16 pens (8-23) can be changed by the user
(See HELP_ LUT_ /PEN).
.\"--------------------------------------------------------------------
.ti -4
2 /HATCH
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[GREG1_\]HISTOGRAM [Array__X Array__Y] /HATCH [Ipen] [Angle] [Separ]
[Phase] [/FILL Icolor] [/BASE Ybase]

Fill the histogram with parallel lines. The pen (default current), the
line orientation in degrees (default 45), separation in physical units
(default 0.25 cm), and phase between 0. and 1. (default 0.) can be
customized. The phase indicate to displace the hatch lines by this
fraction of the separation from a fixed reference.

The histogram is filled down to the base Ybase (default 0.). The
option /FILL can be combined with /HATCH. The histogram contour is not
drawn, if desired this must be done with other call(s) to the command.
.\"====================================================================
.ti -4
1 LABEL
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[GREG1_\]LABEL "Character_ String" [Orientation]  [/APPEND]
[/CENTERING N] [/X [Offset]] [/Y [Offset]]

Writes the string Character String (included between double quotes) at
current pen position or location specified by option, and with current
or requested centering.  The label is written according to the current
or specified Orientation and EXPAND factors. Within a string, the
character "_\" is an escape character and causes the following
action_ :
.nf

		\\X - set mode X                   
		 \X - set mode X for next char     
		 \N - Default character set        
		 \1 - Simplex character set        
		 \2 - Duplex character set         
		 \R - Roman font                   
		 \G - Greek font                   
		 \S - Script font                  
		 \I - toggle italics               
		 \U - superscript                  
		 \D - subscript                    
		 \B - backspace over previous char 
.fi
.\"--------------------------------------------------------------------
.ti -4
2 /APPEND
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[GREG1_\]LABEL /APPEND

Append the label at current pen location. This corresponds to
/CENTERING_ 6.
.\"--------------------------------------------------------------------
.ti -4
2 /CENTERING
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[GREG1_\]LABEL /CENTERING N

The label is oriented with respect to the current location according
to the argument N which can be 1 - 9 for :
.nf
			right    center     left       justified
	label above	  7         8         9
	      centered	  4         5         6
	      below	  1         2         3
.fi
These conventions follow the standard numeric keypads notation.
.\"--------------------------------------------------------------------
.ti -4
2 /X
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[GREG1_\]LABEL /X [Offset]

Put the label centered below the X axis made by BOX.
Offset is an optional argument to indicate the separation between
the label and the axis (in character size, default set by SET LABEL).

.\"--------------------------------------------------------------------
.ti -4
2 /Y
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[GREG1_\]LABEL /Y [Offset]

Put the label centered left of the Y axis made by BOX.
Offset is an optional argument to indicate the separation between
the label and the axis (in character size, default set by SET LABEL).
.\"====================================================================
.ti -4
1 LIMITS
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[GREG1_\]LIMITS [X1 X2 Y1 Y2 [Unit]] [/XLOG] [/YLOG] [/RGDATA]
[/BLANKING Bval Eval] [/REVERSE [X] [Y]] [/VARIABLES Array__X
Array__Y] [/MARGIN [...]]

Sets the coordinates of the plot region. The limits are the user
coordinates of the BOX corners, and in conjunction with the
BOX__LOCATION, specifies the conversion formula between USER and PLOT
coordinates.

The limits can be computed from different data:
.in +4
.ti -2
-_ if LIMITS has no arguments, it will compute automatic limits using
data from the most recent COLUMN X and Y, if any,
.ti -2
-_ if the option /RGDATA is present, the current Regular Grid map is
used, if any,
.ti -2
-_ if the option /VARIABLES Array__X Array__Y is present, the named
SIC variables are used.
.in -4
Options /RGDATA and /VARIABLES are exclusive.

Some special characters are allowed instead of numerical values for
the limits_ :
.nf
      *   Compute automatic limit for this argument
      <   Compute automatic limit for this argument, and take
          the minimum of this value and the precedent limit.
      >   Same as above, but take the maximum.
      =   Keep the precedent value for this limit.
.fi

An additional argument can be used when a projection and a system are
defined. It may take values
.in +4
.ti -2
-_ RADIAN_ : The values are assumed to be normal projected coordinates
from the projection center.
.ti -2
-_ SECOND, MINUTE or DEGREE : The values are converted from the
specified angular unit to radians. They still represent offsets from
the projection center.
.ti -2
-_ ABSOLUTE : The values are assumed to be absolute coordinates on the
sphere. APPROXIMATE corresponding projected coordinates are computed
from these values (the projected coordinates are necessarily
approximate since in general e.g. the upper left and lower left corner
of the box correspond to different absolute Right ascension for
Equatorial system).
.in -4
The default value is the current angle unit as defined by SET_ ANGLE.
.\"--------------------------------------------------------------------
.ti -4
2 /BLANKING
.ti +4
[GREG1_\]LIMITS [Args . . .] /BLANKING Bval Eval

Does not use data points such that abs(Y(i)-Bval)_ <_ Eval. These
points act as separators. Eval negative means no blanking value. Bval
and Eval values default to those specified in SET_ BLANKING.

Note that blanking applies to the intensities (Y) array only, but that
the blanked values in the Y array are used as a mask to compute the X
limits.

This option can not be used with /RGDATA.
.\"--------------------------------------------------------------------
.ti -4
2 /MARGIN
.ti +4
[GREG1_\]LIMITS [Args . . .] /MARGIN [% ...]

Add or modify the default margins applied to the limits. Without this
option, LIMITS adds margins or not depending on the context:
.in +6
.ti -4
LIMITS
.br
with no argument (i.e. guess limits from X and Y buffers) a 5% margin
is implicitly added on all sides
.ti -4
LIMITS /VARIABLE Array__X Array__Y
.br
adds an implicit 5% margin on all sides
.ti -4
LIMITS /RGDATA
.br
adds no margin
.ti -4
LIMITS X1 X2 Y1 Y2
.br
with explicit values, no margins are added
.in -6

If the option /MARGIN is present, margins are added in all cases. The
margin sizes can be customized as follows:
.in +6
.ti -4
/MARGIN
.br
with no values, add a 5% margin on all limits
.ti -4
/MARGIN Val
.br
with a single value, add a "Val" (%) margin on all limits
.ti -4
/MARGIN ValX ValY
.br
with 2 value, add a ValX (%) margin on the X limits, and a ValY (%)
margin on the Y limits
.ti -4
/MARGIN ValXL ValXR ValYL ValYU
.br
with 4 values, add a ValXL (%) margin on the left X limit. Same for
right X limit, lower Y limit, and upper Y limit
.in -6
The margin values are percent of the axis range. They can be negative,
which means the axis range will be truncated.

Note that the * = < > arguments to the command apply AFTER margins are
added.
.\"--------------------------------------------------------------------
.ti -4
2 /REVERSE
.ti +4
[GREG1_\]LIMITS [Args . . .] /REVERSE [X] [Y]

Exchange the left and right limits for X axis, and/or top and bottom
limits for Y axis.
.\"--------------------------------------------------------------------
.ti -4
2 /RGDATA
.ti +4
[GREG1_\]LIMITS [Args . . .] /RGDATA

Specifies that the current Regular Grid array should be used to
compute the (non-specified) limits, instead of the current column
arrays. Logarithmic conversion formulae are not allowed in this case.
The /BLANKING and /VARIABLES options are incompatible with /RGDATA.
.\"--------------------------------------------------------------------
.ti -4
2 /XLOG
.ti +4
[GREG1_\]LIMITS [Args . . .] /XLOG

Specifies that the X conversion formula should be logarithmic. Cannot
be used with the /RGDATA option.
.\"--------------------------------------------------------------------
.ti -4
2 /YLOG
.ti +4
[GREG1_\]LIMITS [Args . . .] /YLOG

Specifies that the Y conversion formula should be logarithmic. Cannot
be used with the /RGDATA option.
.\"====================================================================
.ti -4
1 LOOK
.ti +4
[GREG1_\]LOOK "Command"

Calls the cursor, and executes the specified command each time it is
pressed. The command can be a procedure (e.g. @my__look) and can test
the pressed character which is added at the end as first argument.
Usual exit keys ("E", right-clic, ...) or "*" can be used to exit.
For example, a calling session may look like:
.in +8
GREG-PROMPT> LOOK "SAY You pressed "
.br
You pressed Q
.br
GREG-PROMPT>
.in -8
if "Q" and then "E" have been pressed.
.\"====================================================================
.ti -4
1 PENCIL
.ti +4
[GREG1_\]PENCIL [N] [/COLOUR C] [/DASHED D] [/WEIGHT W] [/DEFAULT]

Selects virtual pen N and defines its attributes in terms of colour,
dashed pattern and weight (thickness). Up to 16 pens can be defined
(0-15). Most plotting commands use the current pen. The major
exception is RGMAP (iso-contouring) which uses the pen 0 (solid and
foreground color by default) and 15 (dotted and blue by default). Some
commands also ignore the dashed patterns, in particular all labels and
the BOX command.
.in +4
.ti -2
- The dashed pattern D must be in range 1 to 8, 1 means solid lines.
.ti -2
- The weight factor W must be a weight number or value. See subtopic
/WEIGHT for details.
.ti -2
-_ The colour index C is a color number or name. See subtopic /COLOUR
for details.
.in -4
PENCIL_ N_ /DEFAULT reset default attributes to Pen number N.
PENCIL_ /DEFAULT reset default attributes for all Pens, as defined at
program initialization.
.\"--------------------------------------------------------------------
.ti -4
2 /COLOUR
.ti +4
PENCIL [N] /COLOUR Arg

Modify the current pen color, or the color of the N-th pen.

The argument can be a color name (subset of the X11 colors catalog),
e.g. RED, LIGHT__SEA__GREEN, MEDIUM__BLUE... The complete list is
available by typing "PENCIL /COLOUR ?". The colors can also be
displayed thanks to the demonstration procedure "@
gag__demo:demo-pencolors.greg". The list is also available in the
character array GTV%COLORS for use in procedures.

There are 3 special color names:
.in +13
.ti -11
BACKGROUND resolves as WHITE on white devices and BLACK on black
devices,
.ti -11
FOREGROUND resolves as BLACK on white devices and WHITE on black
devices,
.ti -11
NEGATIVE inverts the pixel colors below the graphical segment begin
drawn. This ensures that the segment is always visible, whatever the
context. NEGATIVE is supported only for X and PNG devices. Other
devices use the FOREGROUND color as a fallback.
.in -13

The argument can also be an integer value (explicit, or a variable
name, or the result of a math expression) from -1 to 23 with the
following signification:
.in +5
.ti -3
-1 NEGATIVE
.ti -2
0 FOREGROUND
.ti -2
1 RED
.ti -2
2 GREEN
.ti -2
3 BLUE
.ti -2
4 CYAN
.ti -2
5 YELLOW
.ti -2
6 MAGENTA
.ti -2
7 BACKGROUND
.ti -2
8 to 23: those 16 colors can be customized by the user (see HELP_ LUT
/PEN for details). They can be used as any other color, but they also
correspond as the "fill pens" used by the command RGMAP_ /GREY. Those
colors are dynamic, i.e., by default, changing them will also modify
the segments previously drawn with them (see HELP CHANGE LUT).
.in -5
.\"--------------------------------------------------------------------
.ti -4
2 /WEIGHT
.ti +4
PENCIL [N] /WEIGHT Arg

Modify the current pen weight, or the weight of the N-th pen.

The argument can be the pen weight (controling the line width) in
millimiter using the following syntax:
.br
  PEN /WEIGHT 1.23mm
.br
For reference, the weight has to be compared with the current
PLOT__PAGE (default 30cm x 21cm).

The argument can also be an integer index from 1 to 5. They translate
as follows:
.nf
  PEN /WEIGHT 1 => 0.15mm
  PEN /WEIGHT 2 => 0.30mm
  PEN /WEIGHT 3 => 0.45mm
  PEN /WEIGHT 4 => 0.75mm
  PEN /WEIGHT 5 => 1.20mm
.fi

For bitmaps devices (X, PNG), weights lower or equal than 0.15 mm
always translate as 1 pixel width lines. On the other hand, for
vectorial devices (PS, EPS, SVG), all widths are preserved and those
lower than 0.15 mm give different rendering depending on the
viewing/printing application.
.\"====================================================================
.ti -4
1 POINTS
.ti +4

[GREG1_\]POINTS [Xarray Yarray] [/BLANKING Bval [Eval]] [/SIZE Zvalue
[Zarray [Exponent]]] [/MARKER SidesArray StyleArray]

Makes points of the current style (MARKER), size (MARKER and EXPAND),
and orientation (ORIENTATION) at the X and Y coordinates read by
COLUMN, or in the variables Xarray and Yarray.

With the option /SIZE, followed by a real value Zvalue, POINTS will
draw markers of sizes governed by the values of the Z array (or of the
Zarray if specified). Points with Z value equal to Zvalue will have a
marker of size the current marker size. All other markers will have an
AREA proportional to the Z value at each point (i.e. marker radius at
X(i) Y(i) proportional to the square root of Z(i); this power law
exponent can be changed by specifying an additional argument to option
/SIZE).  If Zvalue is equal to zero, the program uses the maximum
absolute value of the Z array instead.

The /BLANKING option can be used to override the current blanking
behaviour, as defined by SET_ BLANKING command. If Eval (defined by
/BLANKING or SET_ BLANKING) is null or positive, blanking is
enabled. If /SIZE is used, blanking applies to the Z (or Zarray)
values, e.g. in a context of a (coordinate,coordinate,intensity)
map. If /SIZE is not used, blanking applies to the Y (or Yarray)
values, e.g. in a context of a (abscissa,intensity) profile.

The /MARKER option can be used to specify a different marker sidedness
and style for each data point.
.\"====================================================================
.ti -4
1 RULE
.ti +4
[GREG1_\]RULE [X] [Y] [/MAJOR] [/MINOR]

Without an argument, or with both X and Y arguments, RULE makes a grid
within the BOX using the current pen. Major or minor ticks or both are
selected according to the options.  With the argument X or Y, the grid
is restricted to X or Y ticks respectively.  The /MAJOR and /MINOR
options can be combined in the same command.
.\"--------------------------------------------------------------------
.ti -4
2 /MAJOR
.ti +4
[GREG1_\]RULE [X] [Y] /MAJOR

Makes a grid at major ticks (This is the default if no option is
given).
.\"--------------------------------------------------------------------
.ti -4
2 /MINOR
.ti +4
[GREG1_\]RULE [X] [Y] /MINOR

Makes a grid at minor ticks.
.\"====================================================================
.ti -4
1 SET
.ti +4
[GREG1_\]SET Argument [Value [...]] [/DEFAULT]

Specify or reset some default value for a parameter used by GreG.
These values may sometimes be overridden for a single command by the
appropriate option (e.g. /BLANKING and SET_ BLANKING).
SET_ Argument_ /DEFAULT reset the default values for the given key.

SET_ /DEFAULT reset all default values of SET including the FONT and
the PLOT__PAGE ; thus the plot cleared. Use PENCIL_ /DEFAULT to reset
the PENCIL definitions, and TICKSPACE_ 0_ 0_ 0_ 0 to reset tick
spacing parameters.

You can use GREG1\SHOW to see the current value of one or all items.
.\"--------------------------------------------------------------------
.ti -4
2 ANGLE__UNIT
.ti +4
[GREG1_\]SET ANGLE__UNIT D

Sets the angle unit for the projection limits. This will become
effective only when a projection is effective, and only affects the
way limits are given and labels written (not internally stored). D may
have the values SECOND, MINUTE, DEGREE, RADIAN.
.\"--------------------------------------------------------------------
.ti -4
2 ACCURACY
.ti +4
[GREG1_\]SET ACCURACY D

Sets the default accuracy (in paper units, i.e. centimeters) used by
the command GREG1\CURVE. It should be set to the plotter resolution,
and must be in range 0.0001 to 1. Default value is 0.01.
.\"--------------------------------------------------------------------
.ti -4
2 AXIS
.ti +4
[GREG1_\]SET AXIS EXPO|NOEXPO [X|Y|Z]
.ti +4
[GREG1_\]SET AXIS BRIEF|NOBRIEF [XDECIMAL|YDECIMAL|XSEXAGESIMAL|YSEXAGESIMAL]

.ti +4
SET AXIS EXPO forces the use of exponential notation for tick labels.

By default (NOEXPO mode), Greg labels the ticks with plain integers
(if abs(value)>=1) or decimal floats (if abs(value)<1) as long as the
label is 6 characters or less. For larger labels, Greg switches to the
exponential notation.

This default mode can lead to inhomogeneous labels, some as
plain integers, others in exponential format. The mode EXPO forces
the use the latter format for all labels.

The labelling rule can be customized for X, Y, or Z (intensities
i.e. wedge labelling). With no argument, the command applies to those
three.

The plain integer/decimal versus exponential formats apply to decimal
and logarithmic axes. Sexagesimal axes have their own labelling rules.

.ti +4
SET AXIS BRIEF|NOBRIEF [XDECIMAL|YDECIMAL|XSEXAGESIMAL|YSEXAGESIMAL]

The BRIEF keyword indicates to the commands G_\AXIS and G_\BOX to
abbreviate the major tick labels, if possible. Abbreviating means
dropping off leading digits which are common to all tick labels of one
axis, in order to make the relevant information (the variable digits)
easier to read. This is particularly suited to axes showing a small
range of values around a large one. This can also help saving place
depending on the axis and its tick labels orientation. Note that the
first tick label is kept entire while the other are abbreviated, and
sign is preserved. The NOBRIEF keyword indicate not to attempt the
abbreviation.

A complementary argument can indicate which kind of axes should be
affected. X and Y refer respectively to horizontal and vertical
axes. The suffix DECIMAL refers to standard linear numbering, while
SEXAGESIMAL refers to sexagesimal notations of any kind. Logarithmic
axes are not affected. By default the command modifies the behavior of
both axes in both supported modes.

Defaults are:
.nf
  XDECIMAL      NOBRIEF
  YDECIMAL      NOBRIEF
  XSEXAGESIMAL  BRIEF
  YSEXAGESIMAL  NOBRIEF
.fi

Here are several examples for axes with 3 major ticks:
.nf
  * NOBRIEF mode:
         123456       123457       123458
      -123456.7   -123456.75    -123456.8
           1000         2000         3000
             -1            0            1
      12h34m56s    12h34m57s    12h34m58s
      12h34m00s    12h36m00s    12h38m00s
  * Same in BRIEF mode:
         123546            7            8
      -123546.7         -.75          -.8
           1000         2000         3000
             -1            0            1
      12h34m56s          57s          58s
      12h34m00s       36m00s       38m00s
.fi
.\"--------------------------------------------------------------------
.ti -4
2 BLANKING
.ti +4
[GREG1_\]SET BLANKING Bval Eval

Define a blanking value Bval with tolerance Eval. Default is no
blanking (i.e. Eval negative). The blanking is used by most curve
plotting commands such as CURVE, CONNECT, POINTS to ignore data points
which verify ABS(Y-Bval) less or equal to Eval. The blanking value is
also used for contours (RGMAP), to avoid plotting contours in pixels
whose value verify the same relation as above. And finally, some
commands require a blanking value to attribute when they are unable to
define a real value_ ; this include RANDOM and MASK.
.\"--------------------------------------------------------------------
.ti -4
2 BOX__LOCATION
.ti +4
[GREG1_\]SET BOX__LOCATION Argument__List

Define the position of the box. The argument list specifies various
options for the box position :
.in +4
.ti -2
- PORTRAIT_ _ _ _ Define a default Portrait oriented box
.ti -2
- LANDSCAPE_ _ _ Define a default Landscape oriented box
.ti -2
- SQUARE_ _ _ _ _ _ Define a square box
.ti -2
- MATCH_ [Gx1_ Gy1_ [Ratio]]_ _ Define a box which matches the ratio
of the physical units. By default, the bottom left corner is placed at
the default position for the current plot page, but can be moved by
specifying arguments Gx1 and Gy1. The box size is adjusted such that
the box occupies as much space as possible within the default box
position for the current plot page type. Ratio is an additional
arguments which indicates a scaling factor for the Y axis.
.ti -4
WARNING_ : The box is computed from the current limits, and will not
change if you compute new limits.
.ti -2
- Gx1_ Gx2_ Gy1_ Gy2_ _ Defines the positions of all box corners in
physical units.
.in -4
The default is LANDSCAPE, PORTRAIT or the default VIEWPORT according
to the current PLOT__PAGE type.
.\"--------------------------------------------------------------------
.ti -4
2 CENTERING
.ti +4
[GREG1_\]SET CENTERING N

Sets the centering option. Default is 0, which means automatic
centering according to the position relative to the box.
.\"--------------------------------------------------------------------
.ti -4
2 CHARACTER
.ti +4
[GREG1_\]SET CHARACTER S

Sets the character size to S physical units. Default is 0.6 .
.\"--------------------------------------------------------------------
.ti -4
2 COMMENT
.ti +4
[GREG1_\]SET COMMENT "Separator"

Specify which character is used to indicate the beginning of a comment
line in formatted input files for command COLUMN. "Separator" is a
single character; typical values are "!", ";", "#", although any
single character can be specified. The default is "!".
.\"--------------------------------------------------------------------
.ti -4
2 COORDINATES
.ti +4
[GREG1_\]SET COORDINATES [System [N]]

Sets the coordinate system for DRAW. The system may be BOX, CHARACTER
or USER. If BOX or CHARACTER, N can be used to specify the point of
the box to which the units refer.  Nine points are available,
following a standard VT100 keypad disposition (see
HELP_ GREG1_\LABEL_ /CENTERING ). N may be 0. In this case, the
nearest point will be used when making annotations with the cursor,
and point 1 will be used in explicit form. The default is BOX 0.
.\"--------------------------------------------------------------------
.ti -4
2 DECIMAL
.ti +4
[GREG1_\]SET DECIMAL [X] [Y]

Specify that labelling of X or Y axis is with a decimal field
(default). Used to revert from sexagesimal labelling (See
HELP_ SET_ SEXAGESIMAL).
.\"--------------------------------------------------------------------
.ti -4
2 EXPAND
.ti +4
[GREG1_\]SET EXPAND E

Expands all characters or markers by a factor E. Default is 1.
.\"--------------------------------------------------------------------
.ti -4
2 FONT
.ti +4
[GREG1_\]SET FONT F

Defines the character font used. F may be SIMPLEX (default) or DUPLEX,
which is nicer but substantially slower, and should be reserved to
publication quality plots. Default is SIMPLEX.
.\"--------------------------------------------------------------------
.ti -4
2 LABEL
.ti +4
[GREG1_\]SET LABEL X|Y [Offset]

Defines the distance between the label (legend drawn by command G_\LABEL)
and the corresponding axis.  The default is 2 character sizes in X, and
6 in Y.  This sometimes require adjustment for publication quality plots.

See also command LABEL /X [Offset] and /Y [Offset].

.\"--------------------------------------------------------------------
.ti -4
2 MARKER
.ti +4
[GREG1_\]SET MARKER Nsides Mstyle Size Orien

Sets the marker type to a polygon of Nsides, of style Mstyle (0-4) and
size Size (physical units).
.in +4
Nsides:
.ti +2
- 0,1 Dots
.ti +2
- 2 Bar
.ti +2
- 3 Triangle
.ti +2
- ...
.br
Mstyle:
.ti +2
- 0 Convex polygon
.ti +2
- 1 Vertex connected
.ti +2
- 2 Starred polygon
.ti +2
- 3 Filled convex polygon (only for Nsides>=3)
.ti +2
- 4 Filled starred polygon (only for Nsides>=3)
.in -4

The default is Nsides=0 Mstyle=0 Size=0 and Orientation 0 (Points,
optimized algorithm). The Orientation is used to plot the marker
(e.g. Horizontal bar for MARKER 2 0 * 0.0, and vertical bar for same
marker MARKER 2 0 * 90.0).

A * instead of a numerical value indicate to keep the last value.
.\"--------------------------------------------------------------------
.ti -4
2 ORIENTATION
.ti +4
[GREG1_\]SET ORIENTATION T [M]

Set orientation of text to T degrees and that of markers to M degrees
(M = T if not specified). The text orientation also controls the
orientation of axes. Default is 0.0 (horizontal).

Text orientation can also be controlled by command DRAW_ TEXT, and
Marker orientation by command SET_ MARKER.
.\"--------------------------------------------------------------------
.ti -4
2 PLOT__PAGE
.ti +4
[GREG1_\]SET PLOT__PAGE X Y

Sets the physical size of plot page. One can use "PORTRAIT" and
"LANDSCAPE" for A4 format with adequate orientation, and square will
give a 30 by 30 cm plot page. Default is LANDSCAPE (A4 30 by 21 cm).
.\"--------------------------------------------------------------------
.ti -4
2 SEXAGESIMAL
.ti +4
[GREG1_\]SET SEXAGESIMAL [X [Nx]] [Y [[Ny]]

Set X axis labelling in sexagesimal notation with Nx decimals
(resp. Y). The default (Nx=1, Ny=0 and no sexagesimal notation) is
nearly always perfect for everybody.

So, this command is used for two restricted purposes:
.in +4
.ti -2
 - to enable sexagesimal notation of axis when a projection is in use,
the system is GALACTIC and the /ABSOLUTE option is required (for
EQUATORIAL systems, the sexagesimal notation is always used in this
case, but the default for GALACTIC system is a decimal representation
of degrees).
.ti -2
 - to specify the number of decimals when using ABSOLUTE labelling
(see BOX_ /ABSOLUTE or AXIS_ /ABSOLUTE).
.in -4
Note that, when a realistic tick spacing is required by the user or
(the default) GreG computes this spacing automatically, labelled
tickmarks will fall on rounded values, so no decimals will appear
(unless the field of view is smaller than a few arc seconds).
.\"--------------------------------------------------------------------
.ti -4
2 SYSTEM
.ti +4
[GREG1_\]SET SYSTEM Name [Equinox]

Specify the coordinate system used in case of projection. The name can
be UNKNOWN, GALACTIC or EQUATORIAL (default equinox is 2000.0 if not
provided). The SYSTEM affects the projection definitions (in
particular the GRID command) and coordinates sent back by the cursor
(different formats are used for each system).
.\"--------------------------------------------------------------------
.ti -4
2 TICKSIZE
.ti +4
[GREG1_\]SET TICKSIZE Major [Minor]

Sets the major tick size to Major (in physical units). The default
value is 0.3. Minor tick size can also be set. If absent, Minor is
half the Major tick size value.
.\"--------------------------------------------------------------------
.ti -4
2 VIEWPORT
.ti +4
[GREG1_\]SET VIEWPORT Px1 Px2 Py1 Py2

Defines the position of the box in terms of fractions of the plot page
size in X and Y. Default is 0.150 0.925 0.125 0.925 .
.\"====================================================================
.ti -4
1 SHOW
.ti +4
[GREG1_\]SHOW Item

.in +4
.ti -2
-_ SHOW_ <SET__key> lists the current value of the associated
parameter(s).
.ti -2
-_ SHOW_ ALL lists the values of all the SET parameters.
.ti -2
-_ SHOW_ PEN lists the current pen definitions (use the PENCIL command
itself for informations on the active pen alone).
.ti -2
-_ SHOW_ PROJECTION lists the current projection used.
.ti -2
-_ SHOW_ [WHERE|LIMITS] [DEGREE|MINUTE|SECOND|RADIAN|ABSOLUTE] shows
the current pen location and plot region limits in Plot coordinates
(i.e. centimeters) and user coordinates.
.br
User coordinates are native user values if no projection is currently
defined, or current angle unit (i.e. according to SET ANGLE) if a
projection is defined.
.br
In the latter case, the second argument overrides the angular unit in
which the user values are displayed.
.ti -2
-_ SHOW without arguments is a synonym of SHOW_ WHERE.
.in -4
.\"====================================================================
.ti -4
1 TICKSPACE
.ti +4
[GREG1_\]TICKSPACE SmallX BigX SmallY BigY

Sets tick intervals (in User coordinates) for BOX or default intervals
for AXIS. SmallX refers to the interval between small tick marks on
the X axis, BigX refers to the interval between large ticks, etc. If
Big is 0, the axis routine will supply its own Big intervals according
to the label limits and use your Small value if non zero. To restore
fully automatic ticking, set Small and Big equal to 0. To suppress
small ticks, specify equal values for Small and Big.

The Small and Big values are meaningless for LOGarithmic axes, which
uses their own conventions. If two major ticks are separated:
.in +4
.ti -2
-_ by one decade, the minor ticks are at all unitary values of the
decade,
.ti -2
-_ by two decades, the minor ticks are at values 2, 5, 10, 20, and 50,
.ti -2
-_ by three or more decades, the minor ticks are at (some of) the
intermediate decades.
.in -4

When using the /ABSOLUTE or /UNIT option for axis-drawing commands,
one has to keep in mind that Small and Big (if not 0) should be
expressed:
.in +4
.ti -2
-_ in seconds of arc for declination or galactic (sexagesimal
notation) axis, /ABSOLUTE option (one can usually multiply by 3600 the
desired tick spacing)
.ti -2
-_ in seconds of time for right ascension axis, /ABSOLUTE option
(multiply by 12)
.ti -2
-_ in seconds, minutes or degrees when option
/UNIT_ [SECOND|MINUTE|DEGREE] is used.
.in -4
Thus in the case of a user-defined tick spacing, TICKSPACE must be
redefined before using another option.
.\"====================================================================
.ti -4
1 VALUES
.ti +4
[GREG1_\]VALUES [Array__X Array__Y [Array__Z]] [/BLANKING Bval [Eval]]

With no argument, VALUES writes (in the shortest possible format) the
values of the Z array at the (X,Y) positions in the box. Three X Y Z
arrays can be specified explicitly instead, e.g. in a context of a
(coordinate,coordinate,intensity) map.

With two X Y arguments, VALUES writes the values of the Y array at the
(X,Y) positions, e.g. in a context of a (abscissa,intensity) profile.

The current character size, expansion factor and fonts are used. Only
points inside the current box are written, but the labels may still
span over the box itself.

Blanking (if any) applies to the plotted values (Y or Z if 2 or 3
arguments resp.). Global blanking values (SET BLANKING) can be
overriden with the option /BLANKING.
.\"====================================================================
.ti -4
1 ENDOFHELP
