NOS Single Beam

The original data sets were extracted from the NOS GEODAS database CD ROMs, available from the National Geophysical Data Center (NGDC). Multiple source files, concatenated NOS bathymetric soundings data sets collected before 1984 as long ago as 1930 from a variety of methods, including depth finders, lead lines, etc. were consolidated into single file. The data within Main Hawaiian Islands were in Old Hawaiian projections and NAD27 projections, and are transformed from the reference of NAD27 to NAD83 datum. The original soundings depths were recorded in fathoms but are now in meters. The projection is geographic, the units are decimal degrees, and the horizontal positioning accuracy is unknown.