Next: Polygon - A polygonal region within a 2-dimensional Frame
Up: AST Class Descriptions
Previous: PointList - A collection of points in a Frame
PolyMap
-
Map coordinates using polynomial functions
- Description:
- A PolyMap is a form of Mapping which performs a general polynomial
transformation. Each output coordinate is a polynomial function of
all the input coordinates. The coefficients are specified separately
for each output coordinate. The forward and inverse transformations
are defined independantly by separate sets of coefficients. If no
inverse transformation is supplied, an iterative method can be used
to evaluate the inverse based only on the forward transformation.
- Constructor Function:
- astPolyMap
-
Inheritance
- The PolyMap class inherits from the Mapping class.
-
Attributes
- In addition to those attributes common to all Mappings, every
PolyMap also has the following attributes:
- IterInverse: Provide an iterative inverse transformation?
- NiterInverse: Maximum number of iterations for iterative inverse
- TolInverse: Target relative error for iterative inverse
-
Functions
- In addition to those functions applicable to all Objects, the
following functions may also be applied to all Mappings:
- astPolyTran: Fit a PolyMap inverse or forward transformation
Next: Polygon - A polygonal region within a 2-dimensional Frame
Up: AST Class Descriptions
Previous: PointList - A collection of points in a Frame
AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
7th December 2012
E-mail:starlink@jiscmail.ac.uk
Copyright (C) 2012 Science \& Technology Facilities Council