Domain - Co-ordinate system domain

Description:

This attribute contains a string that identifies the physical domain of the co-ordinate system that a Frame  describes.

The Domain attribute also controls how Frames align with each other. If the Domain value in a Frame is set, then only Frames with the same Domain value can be aligned with it.

Some Frames are given standard Domain values when they are created (e.g. GRID, FRACTION, PIXEL, AXIS, SKY, SPECTRUM, CURPIC, NDC, BASEPIC, GRAPHICS). Frames created by the user (for instance, using WCSADD) can have any Domain value, but the standard Domain names should be avoided unless the standard meanings are appropriate for the Frame being created.

Type:

String.

Examples:

wcsattrib m51 set domain oldpixel

If the current co-ordinate Frame in the NDF m51 is the PIXEL Frame, then this command takes a `snap-shot' of the PIXEL Frame and stores it as a new Frame with Domain OLDPIXEL in the WCS component. Subsequent changes to the PIXEL Frame (for instance, produced by applications that rotate, or move the contents of the NDF) will not effect the OLDPIXEL Frame, which will thus provide a `frozen' record of the original PIXEL Frame.

Notes:

• All Domain values are converted to uppercase and white space is removed before use.