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Resetting Axis Components  

The axis coordinate system of an NDF may be reset by specifying the component name `Axis' in a call to NDF_RESET, as follows:

      CALL NDF_RESET( INDF, 'Axis', STATUS )

This will cause all the NDF's axis components to become undefined, so that subsequent attempts to read values from any of them will return default values appropriate to the NDF's pixel coordinate system. A subsequent enquiry about the state of the `Axis' coordinate system using NDF_STATE would return a value of .FALSE..

The routine NDF_AREST is also provided for resetting individual axis components. Thus, a particular axis variance array could be reset as follows:

      CALL NDF_AREST( INDF, 'Variance', IAXIS, STATUS )

and any subsequent attempt to read from it would result in the default values being returned.

A list of component names may also be supplied to NDF_AREST, along with an optional IAXIS value of zero to indicate that the resetting operation should apply to all the NDF's axes at once. Thus, the following call:

      CALL NDF_AREST( INDF, 'Wid,Var', 0, STATUS )

would reset all of an NDF's axis width and variance arrays.

Note that a component name of `Centre' may not be supplied to NDF_AREST because all the axis centre arrays behave as a single unit and cannot be independently reset. The only way to remove all axis centre information from an NDF is to reset the entire axis coordinate system via a call to NDF_RESET, as above.



next up previous
Next: Accessing Axis Character Components
Up: AXIS COMPONENTS
Previous: Defining a Default Axis Coordinate System


Starlink User Note 33
R.F. Warren-Smith
11th January 2000
E-mail:rfws@star.rl.ac.uk

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