After the image has been displayed, use the mouse (any button) or keyboard (enter any character) to define each end of the slice. You can define many slices if you wish. When you have marked all the slices you want, click the right button of the mouse (or enter 'X' from the keyboard). You are then offered the choice to redo all the slices if you didn't like them (enter (click the right button or enter 'X' from the keyboard).
Options to fit a Gaussian plus a baseline are available. If you invoke the fitting, it is activated after each of all the slices defined is plotted. With the cursor (any button of a mouse or any characer from the keyboard) you define the initial guesses for the Gaussian parameters. The data, fitted model and residual are then plotted. You can the redo the fitting if you wish (right button of mouse or entering 'X' from keyboard) before proceeding to fit the next slice that you defined.
Options to save the slice values, slice positions and slice models are available.
If you ask CGSLICE to display several sub-plots (e.g. each a different channel from a cube), the slicing is activated after each sub-plot is drawn.
Blanked pixels are not displayed (or saved) and each slice is divided into segments with good points between blanked pixels.
Manipulation of the device colour lookup table is available when you display with a pixel map representation (formerly called a "grey scale")
"contour" (contour) "pixel" (pixel map)
Default is "pixel"
Defaults are 1,1
The transfer function changes available with OPTIONS=FIDDLE are in addition (on top of) to the selections here, but the colour lookup table selections will replace those selected here.
Default is linear between the image minimum and maximum with a b&w lookup table. You can default the intensity range with zeros, viz. "range=0,0,log,-2" say.
"hms" the label is in H M S (e.g. for RA) "dms" the label is in D M S (e.g. for DEC) "arcsec" the label is in arcsecond offsets "arcmin" the label is in arcminute offsets "arcmas" the label is in mas offsets "absdeg" the label is in degrees "reldeg" the label is in degree offsets
The above assume the pixel increment is in radians."abspix" the label is in pixels "relpix" the label is in pixel offsets "abskms" the label is in Km/s "relkms" the label is in Km/s offsets "absghz" the label is in GHz "relghz" the label is in GHz offsets "absnat" the label is in natural coordinates as defined by
the header."relnat" the label is in offset natural coordinates "none" no labels or ticks on the axes
All offsets are from the reference pixel. Defaults are "abspix", LABTYP(1) unless LABTYP(1)="hms" whereupon LABTYP(2) defaults to "dms" (for RA and DEC).
LABTYP(3) can only be "arcsec", "arcmin","arcmas", "reldeg" or "relpix". Default is "arcsec" for RA, DEC, LAT or LONG axes.
"accumulate" means accumulate slices from different sub-plots on
the same display. By default, the slice display is cleared before the slices from the current sub-plot are displayed. The initial slice window extrema are defined from the first sub-plot so slices from succeeding sub-plots may not fit unless you use keywords XRANGE and YRANGE."baseline" means fit a baseline (offset and slope) as well as
a Gaussian when OPTIONS=fit."fiddle" means enter a routine to allow you to interactively
change the display lookup table. You can cycle through a variety of colour lookup tables, as well as alter a linear transfer function by the cursor location, or by selecting predefined transfer functions (linear, square root, logarithmic, histogram equalization)
For hard copy devices (e.g. postscript), a keyboard driven fiddle is offered; you can cycle through different colour tables and invoke the predefined transfer functions, but the linear fiddler is not available. In this way you can make colour hardcopy plots."fit" means fit a Gaussian to each slice. The cursor is used
to make the initial estimates of the Gaussian parameters."grid" means overlay a coordinate grid on the display "noerase" Don't erase a snugly fitting rectangle into which the
"3-axis" value string is written."noimage" means do not generate the pixel map or contour plot
display of the image. Useful if you have specified the slice locations with a text file via the POSIN keyword and you don't want to see the slice locations displayed on the image. The region of the viewsurface used for the slice display is larger with this option active."unequal" means display image with unequal scales in x and y.
The default is that the scales are equal."wedge" means that if you are drawing a pixel map, also draw
and label a wedge to the right of the plot, showing the map of intensity to colour."xrange" means when OPTIONS=fit, use the cursor to define an
x-range outside of which pixels will be excluded from the fit."3value" means label each sub-plot with the appropriate value
of the third axis (e.g. velocity or frequency for an xyv ordered cube, position for a vxy ordered cube)."3pixel" means label each sub-plot with the pixel value of
the third axis.
Both "3pixel" and "3value" can appear, and both will be written on the plot. They are the average values when the third axis is binned up with CHAN. If the third axis is not velocity or frequency, the units type for "3VALUE" will be chosen to be the complement of any like axis in the first 2. E.g., the cube is in vxy order and LABTYP=abskms,arcsec the units for the "3VALUE" label will be arcsec. If LABTYP=abskms,hms the "3VALUE" label will be DMS (if the third [y] axis is declination).
Entries in this file can be white space or comma delimitered or both. All lines beginning with # are ignored.
**** DO NOT USE TABS ****
Double quotes " are used below to indicate a string. The " should not be put in the file. For the string parameters discussed below, you can abbreviate them with minimum match.
Each line describes a slice and should be as follows:
##### The columns in each line must be
1 2 3 4 5 6 7 8 Logical column-----------------------------------------
XOTYPE YOTYPE X1 Y1 X2 Y2 CS CE where
XOTYPE and YOTYPE give the coordinate types of the slice BLC and TRC in the file for the x- and y-directions, respectively. Choose from:
"hms", "dms", "arcsec", "arcmin", "absdeg", "reldeg", "abspix", "relpix", "absnat", "relnat", "absghz", "relghz", "abskms", & "relkms" as described in the keyword LABTYP.Note that %OTYPE does not depend upon what you specified for LABTYP.
X1,Y1 defines the BLC of the slice in the nominated OTYPE coordinate system (X- and Y-OTYPE can be different). X2,Y2 defines the TRC of the slice in the nominated OTYPE coordinate system (X- and Y-OTYPE can be different).
For %OTYPE = "abspix ", "relpix", "arcsec", "arcmin", "absdeg", "reldeg", "absghz", "relghz", "abskms", "relkms", "absnat" and "relnat" X1,Y1 and X2,Y2 are all single numbers.
For %OTYPE = "hms" or "dms", the X and/or Y location is/are replaced by three numbers such as HH MM SS.S or DD MM SS.S. Thus if XOTYPE=hms & YOTYPE=dms then the line should be structured like
hms dms HH MM SS.S DD MM SS.S HH MM SS.S DD MM SS.S CS CE or perhaps hms relpix HH MM SS.S Y1 HH MM SS.S Y2 CS CE
CS to CE is the channel range (image planes) from which the slice is to be extracted. If you specify only CS than the slice is extracted from that channel. If CS=0 then the slice is extracted from all channels. If CS and CE are both omitted, the default is to extract the slice from all channels.