The Transform Library - A high-level interface to coordinate systems

The Transform Library is a new, stand-alone software package developed by the Chandra X-ray Center (CXC), that provides a convenient high-level C++ interface for performing World Coordinate System transformations. The library wraps a subset of the lower-level wcslib functions to provide an easy interface to both users and developers. The Transform library is designed to be used within C++ programs and various scripting environments. Notably, it provides high-level user interfaces in Python and S-Lang for ease of use. The Transform Library consists of C++ classes and methods for performing transformations on input base arrays (table data or image axes), for accessing and manipulating required transform parameters, and for calculating the transform matrix. Transform types include pixel to world coordinate transforms and vice versa, as well as linear transforms and scaling transforms. The design allows for transform chaining, so the user is able to combine multiple transforms into more complex arrangements. The Transform Library will be integrated in the new versions of ChIPS and Sherpa that will be released in CIAO4. In addition, CIAO users will be able to use the library directly via the scripting languages. This provides the ability to easily create highly specialized applications to suit the user's particular needs.