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Writing Import and Export Utilities  

Before writing your own import and export utilities, you should consider using standard ones that already exist. For example, the KAPPA package (SUN/95) contains a general purpose ``fitsimp'' command that can be used to build a specialist NDF extension by importing information from a FITS extension. It is driven by a keyword translation table stored in a text file, so can easily be adapted for different needs. For example, it might be used in an NDF import command as follows:

setenv NDF_IMP_MINE 'fitsimp ndf=^ndf xname=MINE table=$HOME/mine.imp'

Here, mine.imp is the table that drives the importation process. This could be different for each format if necessary. An equivalent extension export utility ``fitsexp'' is also available.

If you find that you must write your own software for this purpose, then the IMG library (SUN/160) provides a convenient programming interface for accessing items of NDF extension information (including individual items within the FITS extension) and should make most import and export utilities straightforward to write. With a little more effort, you can, of course, also use the NDF and HDS libraries, which allow you to construct any form of extension you want.



next up previous
Next: Example: Setting Up an Extension
Up: DATA EXTENSIBILITY
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Starlink System Note 20
R.F.Warren-Smith & D.S.Berry
17th July 2000
E-mail:ussc@star.rl.ac.uk

Copyright © 2000 Council for the Central Laboratory of the Research Councils