  plcon1(z, nx, ny, kx, lx, ky, ly, clevel, nlevel, xg, yg)
  *********************************************************

  plcon1

  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. The arrays xg and yg are used to specify the
  transformation between array indices and world coordinates. 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.

  xg, yg (PLFLT *, input): Pointers to arrays which specify the
  transformation from array indices to world coordinates. These must be
  one-dimensional arrays, used for a transformation of the form: tx=f(x),
  ty=f(y). Function values at locations between grid points are obtained via
  linear interpolation.

  NOTE: this function is intended for use from a Fortran caller only. The C
  user should instead call plconf using the built-in transformation function
  pltr1 for the same capability.

