Overview of the NDF_ Routines

The NDF access routines described in this document all have names of the form:

NDF_$<$name$>$

where $<$name$>$ identifies the operation which the routine performs. These routines provide facilities for performing the following types of operation on NDF data structures:

• Obtaining access to NDFs, for both input and output.

• Creating and deleting NDFs.

• Enquiring about the attributes of NDFs, including their shape and size.

• Enquiring about the attributes of NDF components.

• Reading, writing and resetting NDF component values.

• Enquiring about (and flagging) the presence of bad pixels in NDF components.

• Accessing and handling quality information associated with NDFs.

• Modifying the attributes of NDFs (including their shape and size) and the attributes of their components (such as their numeric type).

• Reading, writing and resetting the values of axis arrays and other axis components associated with NDFs.

• Modifying the attributes of NDF axis components (such as the numeric type of axis arrays).

• Controlling the propagation of NDF components to output data structures.

• Creating, deleting and enquiring about NDF extensions, and obtaining access to components stored within extensions.

• Controlling the propagation of NDF extensions to output data structures.

• Selection and management of sections which refer to subsets or super-sets of NDFs.

• Merging the attributes of NDFs to match the processing capabilities of specific applications.

• Importing and finding NDFs held in HDS container files and copying of NDFs between different HDS locations.

• Recording, accessing and deleting information about the processing history of an NDF.

• Constructing messages about NDFs.

• Controlling access to NDFs.

A full description of each routine can be found in Appendix  of this document.