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Most astronomical images have collections of numeric, character or
logical values associated with them. Typically these consist of
important calibration values, but they are also often used to describe
the history or status of the data. Collections of such data, which are
not actually part of the image array, are known as ``header''
information (this name derives from the fact that FITS1 stores these values at the
beginning - head - of a file). IMG refers to a single piece of such
information as a ``header item'' and a separate set of subroutines
exists to read, write, copy and make enquiries about them.
Next: Reading header items
Up: IMG Simple Image Data Access
Previous: Modifying a copy of an image
IMG Simple Image Data Access
Starlink User Note 160
P.W. Draper
R.F. Warren-Smith
3 March 2003
E-mail:P.W.Draper@durham.ac.uk
Copyright © 2000-2003 Council for the Central Laboratory of the Research Councils