class Continuum and Line Analysis Single-dish Software - IRAM
class Continuum and Line Analysis Single-dish Software - IRAM
class Continuum and Line Analysis Single-dish Software - IRAM
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3.4. COMMUNICATION WITH THE OUTER WORLD 29<br />
• DRAW UPPER Xpos "Text" to draw a vertically oriented text at position Xpos, with a vertical<br />
line connecting the beginning of the text to the current spectrum. This text <strong>and</strong> line are<br />
written at position Xpos, in units of the upper axis. Typically, this comm<strong>and</strong> is used to<br />
mark spectral line identifications.<br />
• DRAW LOWER Xpos "Text" same as above, but with Xpos in units of the lower axis.<br />
• DRAW WINDOW [Level] shows the current line windows by marks on the graphic plot. Level<br />
is an optional arguments indicating at what Y value the marker should be put (Default 0).<br />
• DRAW MASK [Level] same as above but for the current masks.<br />
• DRAW KILL [Channel] kills the specified channel (current one if using the cursor) by attributing<br />
it the “blanking” or “undefined” value.<br />
• DRAW FILL [Channel] Fills the specified channel (current one if using the cursor) by interpolation<br />
between the nearest non-blanked channels. The channel must have been killed<br />
before.<br />
Any other character will not draw anything, but simply returns the cursor position, with corresponding<br />
values of the velocity, frequency, image frequency, channel number.<br />
3.4.3 Importing <strong>and</strong> Exporting Spectra From <strong>and</strong> To FITS<br />
No data reduction package has all the functionalities any user dream about. But a user may<br />
know that the functionality he needs is available in a very specific package. Here comes the need<br />
to exchange data between packages. The current st<strong>and</strong>ard answer to this problem is FITS. <strong>class</strong><br />
to FITS conversion (<strong>and</strong> vice-versa) is done by comm<strong>and</strong> FITS. In addition, all functionalities<br />
provided by the sic comm<strong>and</strong> DEFINE FITS are of course available. For a description of the FITS<br />
format see the original paper by Wells et al. (Astron. <strong>and</strong> Astrophys. Suppl.).<br />
The <strong>class</strong> FITS comm<strong>and</strong> has the following syntax:<br />
FITS READ Filename[.fits]<br />
to read a FITS file <strong>and</strong> create <strong>class</strong> data from it, or<br />
FITS WRITE Filename[.fits] [/BITS Nbits] [/MODE SPECTRUM|INDEX]<br />
to write a FITS file from <strong>class</strong> data.<br />
In addition, default values can be supplied by the SET FITS comm<strong>and</strong>.<br />
SET FITS BITS Nbits<br />
SET FITS MODE Spectrum|Index|None<br />
From FITS to CLASS<br />
FITS READ Filename[.fits]<br />
will read a FITS file <strong>and</strong> create <strong>class</strong> data from it. It is expected to work under the following<br />
conditions:<br />
1. The Filename.fits file contains one spectrum, with (a subset of) the FITS keywords which<br />
are described in the previous section. FITS Keyword redefinition is possible.
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