CSSGRID - tension spline interpolation on a sphere.

       To use CSSGRID, load the NCAR Graphics library ngmath.

       Copyright (C) 2000
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.

UNIX                                                May 2000                                     CSSGRID(3NCARG)

       N           (integer,input) The number of input data points (N > 2).

       RLAT        (real, input) An array containing the latitudes of the input data, expressed in degrees.  The
                   first three points must not be collinear (lie on a common great circle).

       RLON        (real, input) An array containing the longitudes of the input data, expressed in degrees.

       F           (real,   input)   An   array   containing   data  values.  F(I)  is  a  functional  value  at
                   (RLAT(I),RLON(I)) for I = 1 to N.

       NI          (integer, input) The number of rows in the uniform output grid. NI can be 1.

       NJ          (integer, input) The number of columns in the uniform output grid. NJ can be 1.

       PLAT        (real, intput) An array of length NI containing the latitudes the  output  grid  lines.   The
                   values in PLAT should be in degrees.

       PLON        (real,  intput)  An  array of length NJ containing the longitudes the output grid lines.  The
                   value in PLON should be in degrees.

       FF          (real, output) An NI by NJ array containing the desired interpolated values. FF(I,J)  is  the
                   interpolated value at the coordinate specified by PLAT(I) and PLON(J) for I = 1 to NI and J =
                   1 to NJ.

       IWK         (integer, input) An integer workspace of length 27*N.

       RWK         (double  precision,  input)  A  work array dimensioned for 13*N.  Note that RWK must be typed
                   DOUBLE PRECISION.

       IER         (integer, output) An error return value.  If IER is  returned  as  0,  then  no  errors  were
                   detected. If IER is non-zero, then refer to the man page for cssgrid_errors for details.

       CSSGRID - tension spline interpolation on a sphere.

       css_overview, csstri, cssgrid_errors

       Complete documentation for Cssgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/cssgrid/csshome.html

       CALL CSSGRID (N, RLAT, RLON, F, NI, NJ, PLAT, PLON, FF, IWK, RWK, IER)

       CSSGRID is called to find an interpolating tension spline for data randomly positioned on a sphere.