
plcont: Contour plot 

DESCRIPTION:

    This function is used in examples 9,14,16,22. 

SYNOPSIS:

plcont(f, nx, ny, kx, lx, ky, ly, clevel, nlevel, pltr, pltr_data)

ARGUMENTS:

    f (const PLFLT * const *, input) :      Pointer to a vectored
    two-dimensional array containing data to be contoured. 

    nx, ny (PLINT, input) :    Physical dimensions of array f. 

    kx, lx (PLINT, input) :    Range of x indices to consider. 

    ky, ly (PLINT, input) :    Range of y indices to consider. 

    clevel (const PLFLT *, input) :    Pointer to array specifying levels
    at which to draw contours. 

    nlevel (PLINT, input) :    Number of contour levels to draw. 

    pltr (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer) , input) : 
      Pointer to function that defines transformation between indices
    in array f and the world coordinates (C only).    Transformation
    functions are provided in the PLplot library: pltr0 for identity
    mapping, and pltr1 and pltr2 for arbitrary mappings respectively
    defined by one- and two-dimensional arrays.  In addition,
    user-supplied routines for the transformation can be used as well.
     Examples of all of these approaches are given in the PLplot
    documentation. The transformation function should have the form
    given by any of pltr0, pltr1, or pltr2. Note that unlike plshades
    and similar PLplot functions which have a pltr argument, plcont
    requires that a transformation function be provided in the C
    interface.  Leaving  pltr NULL will result in an error. 

    pltr_data (PLPointer, input) :    Extra parameter to help pass
    information to pltr0, pltr1, pltr2, or whatever routine that is
    externally supplied. 
