Notes
-----

For the **-Qs** option: The PostScript language has no mechanism for smoothly varying
colors within a polygon, so colors can only vary from polygon to
polygon. To obtain smooth images this way you may resample the grid
file(s) using :doc:`grdsample` or use a finer grid size when running
gridding programs like :doc:`surface` or :doc:`nearneighbor`. Unfortunately,
this produces huge PostScript files. The alternative is to use the
**-Qi** option, which computes bilinear or bicubic continuous color
variations within polygons by using scanline conversion to image the polygons.