||This APG is primarily intended for parameters that specify the dimensions: x, y (e.g. latitude, longitude) z (e.g. height above sea level/sea floor, depth/pressure) t (e.g. date/time, elapsed time) However, there are other parameters, such as general purpose quality control flags, sequence numbers, platform orientation (heading)/velocity, sampling duration/quantity (e.g. volume filtered) that have been included in the BODC dictionary mapping. It is inevitable that a grouping such as this will become the final resting place for parameters that do not fit into any other existing APG. The mappings to this group therefore require periodical review. Note the potential for problems with confusion between pressure/depth as a z co-ordinate, as a sea level parameter (variation with time), or as a seafloor topography (bathymetry) measurement. Each of these should be assigned a different parameter if sensible grouping is to be possible. BODC currently has problems in this area that have been temporarily resolved by mapping ambiguous pressure/depth parameters into the Other Physical Oceanographic Measurements APG until the problems can be resolved as part of a planned future database restructure.