YAML itself does not define a way to store coordinate systems or transformations - such
definitions must be provided by a suitable WCS-oriented schema. The scheme to use is
defined by the YamlEncoding attribute. Currently, the only schema supported by
this class is
" , defined by the Space Telescope Science Institute. (see
http://asdf-standard.readthedocs.io). At some point in the future support will be added
for the AST NATIVE scheme.
Normally, when you use a YamlChan, you should provide
functions which connect it to an external data store by reading and writing the
resulting text. These functions should perform any conversions needed between
external character encodings and the internal ASCII encoding. If no such functions
are supplied, a Channel will read from standard input and write to standard
This class uses the limyaml library to read and write yaml. If the libyaml library cannot be found when the AST library is configured, then an error will be reported if any YamlChan methods are invoked.