1Cssgrid(3NCARG)                  NCAR GRAPHICS                 Cssgrid(3NCARG)
2
3
4

NAME

6       Cssgrid is a software package in the ngmath library that implements a
7       tension spline interpolation algorithm to fit a function to input data
8       randomly located on the surface of a sphere.
9
10       There are user-settable parameters that control various aspects of the
11       algorithm, the most important of which is the tension factor that
12       controls the level a tautness of the spline fit.  This varies from pure
13       cubic spline interpolation for a tension factor of 0. to near linear
14       interpolation for a large tension factor.  By default, the tension
15       factor is automatically computed to optimize certain fitting criteria.
16
17       The output is a set of values at coordinates on a user-specified
18       lat/lon grid (which can be a single point).  Procedures also exist for
19       finding a Dealunay triangulation and Voronoi polygons.
20
21       Functionally equivalent Fortran, C, and NCL interfaces are provided.
22       Fortran and C codes are available in both single and double precision.
23
24       Cssgrid is based on the work of Robert Renka and his packages STRIPACK
25       and SSRFPACK.
26

SYNOPSIS

28       Fortran
29       -----------------------------
30        CSSGRID  - interpolation on a sphere
31        CSSTRI   - calculates Delaunay triangulation
32        CSVORO   - calculates Voronoi polygons
33        CSS2C    - converts from lat/lon to Cartesian coordinates
34        CSC2S    - converts from Cartesian to lat/lon coordinates
35        CSSETI   - set values for integer-valued parameters
36        CSGETI   - retrieve values for integer-valued parameters
37        CSSETR   - set values for real valued parameters
38        CSGETR   - retrieve values for real valued parameters
39        CSSETD   - set values for double precision-valued parameters
40        CSGETD   - retrieve values for double precision-valued parameters
41        CSSGRIDD - interpolation on a sphere (double precision entry)
42        CSSTRID  - calculates Delaunay triangulation (double precision entry)
43        CSVOROD  - calculates Voronoi polygons (double precision entry)
44        CSS2CD   - converts from lat/lon to Cartesian coordinates (double
45       precision entry)
46        CSC2SD   - converts from Cartesian to lat/lon coordinates (double
47       precision entry)
48       -----------------------------
49        c_cssgrid  - interpolation on a sphere
50        c_csstri   - calculates Delaunay triangulation
51        c_csvoro   - calculates Voronoi polygons
52        c_css2c    - converts from lat/lon to Cartesian coordinates
53        c_csc2s    - converts from Cartesian to lat/lon coordinates
54        c_csseti   - set values for integer-valued parameters
55        c_csgeti   - retrieve values for integer-valued parameters
56        c_cssetr   - set values for real valued parameters
57        c_csgetr   - retrieve values for real valued parameters
58        c_cssetd   - set values for double precision-valued parameters
59        c_csgetd   - retrieve values for double precision-valued parameters
60        c_cssgridd - interpolation on a sphere (double precision entry)
61        c_csstrid  - calculates Delaunay triangulation (double precision
62       entry)
63        c_csvorod  - calculates Voronoi polygons (double precision entry)
64        c_css2cd   - converts from lat/lon to Cartesian coordinates (double
65       precision entry)
66        c_csc2sd   - converts from Cartesian to lat/lon coordinates (double
67       precision entry)
68

ACCESS

70       To use Cssgrid entries, load the NCAR Graphics library ngmath.
71

SEE ALSO

73       cssgrid_params cssgrid_errors
74
75       Complete documentation for Cssgrid is available at URL
76       http://ngwww.ucar.edu/ngdoc/ng/ngmath/cssgrid/csshome.html
77

79       Copyright (C) 2000
80       University Corporation for Atmospheric Research
81
82       The use of this Software is governed by a License Agreement.
83
84
85
86UNIX                               May 2000                    Cssgrid(3NCARG)
Impressum