VERTCRS["NGG1977 height",
    VDATUM["Nivellement General Guyanais 1977"],
    CS[vertical,1],
        AXIS["gravity-related height (H)",up,
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Geodesy, engineering survey, topographic mapping."],
        AREA["French Guiana - onshore."],
        BBOX[2.11,-54.61,5.81,-51.61]],
    ID["EPSG",5755]]