[fitsbits] INHERIT and Hierarchical Grouping

[William Pence]

Perhaps this EXTTYPE convention should be written up and submitted to 
the Registry of conventions.  Even though this convention only defines a 
single new keyword (EXTTYPE), it is a rather fundamental concept that is 
relevant to many FITS files, and it also has implications on how the 
reserved EXTNAME keyword should be used.

Bill

Malcolm J. Currie wrote:
> Don added these EXT* keywords specifically with Starlink hierarchical
> data in mind.  It's my fault for not picking the omission of an EXTTYPE
> keyword from the extension paper before publication.  It only came
> blindly obvious once I tried to convert a Starlink NDF dataset into FITS
> and back to the hierarchical format.  Once I'd added an EXTTYPE to
> record the component data type, to supplement the path within the
> hierarchy stored in EXTNAME, it was possible to convert to FITS and back
> to NDF recovering the original structure.
> 
-- 
____________________________________________________________________
Dr. William Pence                       pence at milkyway.gsfc.nasa.gov
NASA/GSFC Code 662       HEASARC        +1-301-286-4599 (voice)
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