% @(#)converdesc.hlq	17.1.1.1 (ESO-DMD) 01/25/02 17:43:23 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      convercoor.hlq
%.AUTHOR     JDP, IPG/ESO
%.KEYWORDS   MIDAS, help files, CONVERT/DESCR_MATRIX
%.PURPOSE    On-line help file for the command: CONVERT/DESCR_MATRIX
%.VERSION    1.0  010223: Creation KB
%----------------------------------------------------------------
\se
SECTION./DESC
\es\co
CONVERT/DESCR_MATRIX					23-FEB-2001  KB
\oc\su
CONVERT/DESCR_MATRIX image  table  direction
              dscroot[,first[,last]]  dscsub1,dscsub2,...  del_flag
\us\pu
Purpose:    
          Convert a descr. matrix in FITS convention to a table and back.
\up\sy
Syntax:     
	  CONVERT/DESCR_MATRIX image  table  direction
                dscroot[,first[,last]]  dscsub1,dscsub2,...  del_flag
\ys\pa
          image = name of image frame
\ap\pa
          table = name of Midas table
               will be created if descr's to table conversion 
\ap\pa
          direction = indicate direction of conversion
	       "ds-t" or "t-ds" for descriptors to table or table to
               descriptors
               defaulted to `ds-t'
\ap\pa
          dscroot[,first[,last]] = part of the descriptor (FITS keyword)
               to which the matrix indices are appended;
               first = optional first index, defaulted to 1
               last = optional last index, should be omitted if all
                      descriptors should be converted
\ap\pa
          dscsub1,dscsub2,... = the different strings which are appended
               to `dscroot'xyz (xyz = running no.);
               currently max. 10 sub descriptors possible
               in other words, the table is limited to 10 columns;
               only applicable for direction = ds-t
\ap\pa
          del_flag = 0 (No) or 1 (Yes) delete the descriptors after the
               conversion to table elements;
               only applicable for direction = ds-t
\ap\sa
See also: 
          READ/DESCR, INDISK/FITS, SET/MIDAS DSCCOPY=
\as\no
Note:  
          The no. of rows created/processed is stored in keyword OUTPUTI(9).

          This command should be used to tame these excessive FITS headers
          as e.g. written by VIMOS.
          The VIMOS data files have 6 keywords (TYPE, ID, X, Y, DIMX, DIMY)
          in the FITS header for each slit of the instrument, specified via
          ESO.INS.SLIT#.TYPE, ESO.INS.SLIT#.ID, ESO.INS.SLIT#.X, ...
          where # goes from 1 to 504, currently.   
          That makes more than 3000 FITS  keywords (descriptors) ...
          Processing images usually involves copying all descriptors of the
          input frame to the result frame.
          Thus, if for any image operation involving VIMOS data you have to
          also copy all those descriptors, execution speed will converge
          towards zero...
\on\exs
Examples:
\ex
          CONVERT/DESC vimos slittab ds-t eso.ins.slit type,id,x,y,dimx,dimy 1
            This command will create a table `slittab.tbl' with 6 columns,
            labeled :TYPE, :ID, :X, :Y, :DIMX, :DIMY and populate it with
            the corresponding descriptors of `vimos.bdf'.
            Assuming the last descriptor of that list had index 504,
            i.e. there is ESO.INS.SLIT504.TYPE, ...
            the table will have 504 rows.
            The descriptors will be deleted.
\xe \ex
          CONVERT/DESC vimos bintab t-ds eso.ins.slit 
            Will build up descriptors like ESO.INS.SLIT#.XYZ for each column
            labeled :XYZ of `bintab.tbl'
\xe \ex
          INDISK/FITS vimos.fits vimosdata
          CONVERT/DESC vimosdata slittab ds-t eso.ins.slit 
                       type,id,x,y,dimx,dimy 1
          OUTDISK/SFITS vimosdata.bdf,slittab.tbl newvimos.fits

            The commands above convert such a set of descriptors to a table 
            extension of the data file. 
\xe \sxe