In we used the ZoomMap as an example of a Mapping. We saw how it could be used to transform coordinates from its input to its output and back again (). We also saw how its behaviour could be controlled by setting various attributes, such as the Zoom factor and the Report attribute that made it display coordinate values as it transformed them.
In this section, we will look at Mappings a bit more thoroughly and
explore the behaviour which is common to all the Mappings provided by
AST. This is good background for what follows, because many of the
Objects we discuss later will also turn out to be Mappings in various
AST A Library for Handling World Coordinate Systems in Astronomy