| Cssgrid(3NCARG) | NCAR GRAPHICS | Cssgrid(3NCARG) |
NAME¶
cssgrid - fit a tension spline interpolation to a functionDESCRIPTION¶
Cssgrid is a software package in the ngmath library that implements a tension spline interpolation algorithm to fit a function to input data randomly located on the surface of a sphere.There are user-settable parameters that control various aspects of the algorithm, the most important of which is the tension factor that controls the level a tautness of the spline fit. This varies from pure cubic spline interpolation for a tension factor of 0. to near linear interpolation for a large tension factor. By default, the tension factor is automatically computed to optimize certain fitting criteria.
The output is a set of values at coordinates on a user-specified lat/lon grid (which can be a single point). Procedures also exist for finding a Dealunay triangulation and Voronoi polygons.
Functionally equivalent Fortran, C, and NCL interfaces are provided. Fortran and C codes are available in both single and double precision.
Cssgrid is based on the work of Robert Renka and his packages STRIPACK and SSRFPACK.
SYNOPSIS¶
Fortran----------------------------- CSSGRID - interpolation on a sphere CSSTRI - calculates Delaunay triangulation CSVORO - calculates Voronoi polygons CSS2C - converts from lat/lon to Cartesian coordinates CSC2S - converts from Cartesian to lat/lon coordinates CSSETI - set values for integer-valued parameters CSGETI - retrieve values for integer-valued parameters CSSETR - set values for real valued parameters CSGETR - retrieve values for real valued parameters CSSETD - set values for double precision-valued parameters CSGETD - retrieve values for double precision-valued parameters CSSGRIDD - interpolation on a sphere (double precision entry) CSSTRID - calculates Delaunay triangulation (double precision entry) CSVOROD - calculates Voronoi polygons (double precision entry) CSS2CD - converts from lat/lon to Cartesian coordinates (double precision entry) CSC2SD - converts from Cartesian to lat/lon coordinates (double precision entry)
----------------------------- c_cssgrid - interpolation on a sphere c_csstri - calculates Delaunay triangulation c_csvoro - calculates Voronoi polygons c_css2c - converts from lat/lon to Cartesian coordinates c_csc2s - converts from Cartesian to lat/lon coordinates c_csseti - set values for integer-valued parameters c_csgeti - retrieve values for integer-valued parameters c_cssetr - set values for real valued parameters c_csgetr - retrieve values for real valued parameters c_cssetd - set values for double precision-valued parameters c_csgetd - retrieve values for double precision-valued parameters c_cssgridd - interpolation on a sphere (double precision entry) c_csstrid - calculates Delaunay triangulation (double precision entry) c_csvorod - calculates Voronoi polygons (double precision entry) c_css2cd - converts from lat/lon to Cartesian coordinates (double precision entry) c_csc2sd - converts from Cartesian to lat/lon coordinates (double precision entry)
ACCESS¶
To use Cssgrid entries, load the NCAR Graphics library ngmath.SEE ALSO¶
cssgrid_params cssgrid_errorsComplete documentation for Cssgrid is available at URL
http://ngwww.ucar.edu/ngdoc/ng/ngmath/cssgrid/csshome.html
COPYRIGHT¶
Copyright (C) 2000University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.
| May 2000 | UNIX |