Description: A depth area is a water area whose depth is within a defined range of values. Intertidal areas are encoded as depth areas. These do not have to include soundings. The depth range within a depth area is defined by the attributes 'DRVAL1' and 'DRVAL2'. Distinction: depth contour; dredged area; sounding; obstruction; sea area/named water area; unsurveyed area; wreck
Description: Generally, an area where the mariner has to be made aware of circumstances influencing the safety of navigation. Distinction: wrecks; underwater rocks; obstructions; unsurveyed area;