  plcon0(z, nx, ny, kx, lx, ky, ly, clevel, nlevel)
  *************************************************

  plcon0

  Draws a contour plot of the data in z[nx][ny], using the nlevel contour
  levels specified by clevel. Only the region of the array from kx to lx and
  from ky to ly is plotted out. Contour plots for more information.

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

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

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

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

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

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

  NOTE: this function is intended for use from a Fortran caller only. The C
  user should instead call plcont using the built-in transformation function
  pltr0 for the same capability.

