**-C**\ [*cpt*\|\ *master*\ [**+h**\ [*hinge*]][**+u**\|\ **U**\ *unit*] \|\ *color1,color2*\ [,\ *color3*\ ,...]]
    Name of a CPT file. If given a GMT Master soft-hinge CPT (see :ref:`Of Colors and Color Legends`) then
    you can enable the hinge at data value *hinge* [0] via **+h**, whereas for hard-hinge CPTs you
    can adjust the location of the hinge [0].  For other CPTs, you may convert their *z*-values
    from meter to another distance unit (append **+U**\ *unit*) or from another unit to meter (append **+u**\ *unit*),
    with *unit* taken from **e**\|\ **f**\|\ **k**\|\ **M**\|\ **n**\|\ **u**.
    Alternatively, give *color1,color2*\ [*,color3*\ ,...]
    to build a linear continuous CPT from those colors automatically,
    where *z* starts at 0 and is incremented by one for each color.
    In this case *color*\ **n** can be a r/g/b triplet, a color name,
    or an HTML hexadecimal color (e.g. #aabbcc).
