VERTCRS["HKCD depth",
    VDATUM["Hong Kong Chart Datum"],
    CS[vertical,1],
        AXIS["depth (D)",down,
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Hydrography and nautical charting."],
        AREA["Hong Kong - offshore."],
        BBOX[22.13,113.76,22.58,114.51]],
    ID["EPSG",5739]]