NNGETSLOPED - retrieve the double precision slope at a specified coordinate.

       To use NNGETSLOPED, 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                                             March 1997-1998                             NNGETSLOPED(3NCARG)

       I           (Integer,  Input) - A subscript indexing the first dimensioned variable in the output grid of
                   the most recent call to NATGRIDD.

       J           (Integer, Input) - A subscript indexing the second dimensioned variable in the output grid of
                   the most recent call to NATGRIDD.

       SLOPE       (Double precision, Output) - The slope at the grid point Z(I,J), where Z is the  output  grid
                   in the most recent call to NATGRIDD.

       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 natgrid_errors for details.

       NNGETSLOPED - retrieve the double precision slope at a specified coordinate.

       natgrid, natgridd, natgrid_params.

       Complete documentation for Natgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/natgrid/nnhome.html

       CALL NNGETSLOPED (I,J,SLOPE,IER)