VERTCRS["NIVELLEMENT GENERAL DE GUYANE (NGG) 1977",
    VDATUM["NIVELLEMENT GENERAL DE GUYANE (NGG) 1977"],
    CS[vertical,1],
        AXIS["gravity-related height (H)",up,
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["LOCALE A CARACTERE LEGAL"],
        AREA["GUYANE FRANCAISE"],
        BBOX[2.05,-54.95,5.95,-51.05]],
    ID["IGNF","GUYA77"]]