Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/computing/software/gipsy/tsk/rfits.dc1 Дата изменения: Sun Jan 2 10:41:12 2000 Дата индексирования: Fri Jan 16 00:08:02 2009 Кодировка: Поисковые слова: южная атлантическая аномалия

Program: RFITS

Purpose: Load FITS files from tape into a GIPSY set.

Category: FITS, TAPES, UTILITY

File: rfits.c

Author: K.G. Begeman

Description: The program RFITS is designed to load FITS files into
GIPSY sets. Since the F in FITS stands for flexible,
it is not that simple to comprehend the data structure
which is to be loaded. Therefore RFITS needs a lot of
interaction with the user, and the user must know what
is on tape and where it is on tape.
Since this program must also be flexible, it will always
be in devellopment, which means that there will be
a constant interaction between the user and the programmer.
So don't hesitate to bring forward suggestions for
improvement, or even criticism.

Keywords:

*** AUTO= Try to run in automatice mode [Y].
In automatice mode the program will do its best to
comprehend the FITS structure on tape. FITS items for
which the program has some reasonable defaults will
not be asked. In non-automatic mode all items will be
asked.

*** NODATA= Create only set headers [N].
With NODATA=Y no data is read, only the set headers
are created.

*** HISTORY= Copy history information from FITS file to Set header [Y].

*** COMMENT= Copy comments from FITS file to Set Header [Y].

FITSFILE= Name of file with FITS data [read from tape device].
If a file name is entered, the keywords INTAPE= and
INFILES= will be skipped. This keyword, and all the
following keywords are repeated. After the first filename
is read, the default will change to [RFITS quits].

INTAPE= Tape device to load from [list of all tape devices].

INFILES= File numbers on tape to load data from [RFITS quits].
Maximum number of files is 200. The first time this
keyword is asked, the current file on tape has file
number 0, the previous file (if present) has file number
-1 and the next file has file number +1. All numbers will
be relative to this initial position. It is also important
to know that the program reads the tape in forward direction,
meaning that it does not care about the order of file numbers
entered by the user.
This keyword, and all the following keywords are repeated.

OUTSET= Set to load data into. The following keywords depend
on whether the set already exists or not.

*** BLANK= Redefine the FITS BLANK value as specified in the FITS
header [value from FITS header]. This option is useful
if the program which created the FITS file made a
mistake.

--------------------------------------------------------
The following keywords deal with the FITS structure on
tape. If the program comprehends this structure, the
keywords will be hidden. You can force all keywords to
be prompted with AUTO=N.
The asterix in the keyword will be replaced by the
corresponding axis number.
--------------------------------------------------------

CTYPE*= Enter the corresponding axis name. Default is chosen as
smart as possible. If the set does not exist, the user may
type any other legal axis name. If the axis name found in
the FITS file is NOT a correct axis name, the user must
supply a legal axis name.
It is also possible to SKIP an axis or to HIDE an axis.
The default will again be chosen as smart as possible.
NOTE: Frequency axes to which a velocity system is
attached must be indicated by FREQ-OHEL, FREQ-OLSR,
FREQ-RHEL or FREQ-RLSR.
NOTE: This keyword is also asked (hidden) if the set
does not yet exist. It will ask for extra axes names
to be added to the new set, all with length 1.

CUNIT*= Enter the units of the axis on the FITS tape. This
keyword only appears if the set does not yet exist
and the corresponding FITS descriptor is not present.
Default depends on CTYPE and is normally as prescribed
by the FITS standard.

CRVAL*= Enter the reference value on the axis. This keyword only
appears if the set does not yet exist.
Default will be chosen as best we can.

CDELT*= Enter the pixel separation along the axis. This keyword only
appears if the set does not yet exist.
Note: WSRT data might have the wrong sign for CDELT3.

*** LIMITS*= Enter the range in grids along the axis [whole axis].
If the set does already exist, this keyword will not be asked.
Note that GIPSY does not allow to extend axes in any
direction. Only the last axis in a GIPSY set may be
extended, so with this keyword you can make room for
data which should be loaded at lower grid positions.

GRID*= Enter the first grid position along the axis [first on axis].
This keyword is only asked if the set does not yet exist.
Default will be chosen as best we can.

FREQ0= Rest frequency of observation in Hz. This keyword only
appears if FITS descriptor not found in FITS file and
the axis is a frequency axis with velocity information.

VEL= Velocity of first grid on axis. This keywords is only asked
for old FITS files which have been written by VMS GIPSY.

Example: RFITS,AUTO=N
RFITS,INTAPE=IMPORT
RFITS,INFILES=31
RFITS,OUTSET=NGC4214
RFITS,CTYPE1=RA-NCP
RFITS,CUNIT1=
RFITS,LIMITS1=
RFITS,GRID1=
RFITS,CTYPE2=DEC-NCP
RFITS,CUNIT2=
RFITS,LIMITS2=
RFITS,GRID2=
RFITS,CTYPE3=FREQ-OHEL
RFITS,CUNIT3=MHZ
RFITS,CDELT3=-2.5/64
RFITS,LIMITS3=1 32
RFITS,GRID3=32
RFITS,FREQ0=
RFITS,CTYPE4=
RFITS,CTYPE5=
RFITS,INFILES=

Updates: May 24, 1990: KGB, Document created.
Nov 26, 1991: KGB, Automatic mode implemented.
Feb 26, 1993: KGB, Modification for NEWSTAR FITS.
Mar 19, 1993: KGB, Extending the dimensions of new set.
Apr 23, 1993: KGB, Bug repaired, keyword NODATA added.
Apr 14, 1994: KGB, Bug when reading multiple NMAP cubes repaired.
Feb 5, 1996: KGB, Keyword FITSFILE= implemented.
Dec 14, 1999: VOG, Allow axis names X1...Xn as default for
missing CTYPEs in FITS header