### A Release Notes

The document is substantially unchanged from the 1989 October version. The recent changes (SGP/38.3) are:

• a correction to the formula for evalution of the normalised co-ordinates for a Chebyshev polynomial,
• the addition of a $<$POLYNOMIAL$>$ variant for B-Splines, and
• some formatting changes.

Note that this document does not describe additional structures created since the late 1990s that are commonly found in NDFs, such as WCS and PROVENANCE.