TBINFO
Name
TBINFO
Purpose
Return an informational IDL structure from a FITS binary table header.
Calling Sequence
tbinfo, h, tb_str, [ERRMSG = ]
Inputs
h - FITS binary table header, e.g. as returned by READFITS()
Outputs
tb_str - IDL structure with extracted info from the FITS binary table
header. Tags include
.tbcol - starting column position in bytes, integer vector
.width - width of the field in bytes, integer vector
.idltype - idltype of field, byte vector
7 - string, 4- real*4, 3-integer*4, 5-real*8
.numval - repeat count, longword vector
.tunit - string unit numbers, string vector
.tnull - integer null value for the field, stored as a string vector
so that an empty string indicates that TNULL is not present
.tform - format for the field, string vector
.ttype - field name, string vector
.maxval- maximum number of elements in a variable length array, long
vector
.tscal - pointer array giving the scale factor for converting to
physical values, default 1.0
.tzero - pointer array giving the additive offset for converting to
physical values, default 0.0
.tdisp - recommended output display format
All of the output vectors will have same number of elements, equal
to the number of columns in the binary table.
The .tscal and .tzero values are stored as pointers so as to preserve
the individual data types (e.g. float or double) which may differ
in different columns. For example, to obtain the value of TSCAL for
the third column use *tab_str.tscal[2]
Optional Input Keyword
/NOSCALE - if set, then the TSCAL* and TZERO* keywords are not extracted
from the FITS header, and the .tscal and .tzero pointers do not
appear in the output structure.
Optional Output Keyword
ERRMSG = if present, then error messages are returned in this keyword
rather than displayed using the MESSAGE facility
Procedures Used
SXPAR()
Notes
For variable length ('P' format) column, TBINFO returns values for
reading the 2 element longward array of pointers (numval=2,
idltype = 3, width=4)
History
Major rewrite to return a structure W. Landsman August 1997
Added "unofficial" 64 bit integer "K" format W. Landsamn Feb. 2003
Store .tscal and .tzero tags as pointers, so as to preserve
type information W. Landsman April 2003
Treat repeat count for string as specifying string length, not number
of elements, added ERRMSG W. Landsman July 2006
Treat logical as character string 'T' or 'F' W. Landsman October 2006
Added NOSCALE keyword W. Landsman March 2007