Editing the Data Structures

There are facilities for editing HDS  components, though these should be used with care, lest you invalidate the file. For instance, if you were to erase the DATA_ARRAY component of an NDF , the file would no longer be regarded as an NDF by applications software.

In KAPPA, ERASE will let you remove any component from within an HDS container file, but you have to know the full path to the component. SETEXT has options to erase extensions and their contents, without needing to know how these are stored within the HDS file. It also permits you to create and rename extension components, and assign new values to existing components. There are a number of commands for manipulating FITS-header information stored in the NDF's FITS extension. These are described in the FITS airlock.

FIGARO offers some additional tasks (CREOBJ, DELOBJ, and RENOBJ) for editing HDS components.