USGS Geologic Division Coastal and Marine Geology Program GOMAINE

Construction of Digital Bathymetry for the Gulf of Maine


A system-wide description of the seafloor topography is a basic requirement for most coastal oceanographic studies. The necessary detail of the topography obviously varies with application, but for many uses, a nominal resolution of 0.5 or 1 km is appropriate. Creating a digital bathymetric grid with this level of resolution can be a complex procedure due to a multiplicity of data sources, data coverage's, datum's and interpolation procedures. The objective here was to construct a 15 arc second (~0.5 km) and  30 arc second (~1.0 km) bathymetric grids for the Gulf of Maine (Longitude = 71.5 - 63 W, Latitude = 39.5 - 46 N).  In addition to the grids themselves, valuable ancillary products such as sounding data with obvious bad points removed, digital bathymetric contour lines and shaded-relief maps were generated.

The first step in compiling a composite bathymetric dataset was to find all available digital hydrographic data for the Gulf of Maine region. Given the variety of input data, the specific characteristics of each dataset had be taken into account before incorporation into the composite dataset. These characteristics included the method of collection, survey resolution (sampling frequency), method and units of navigational positioning, horizontal and vertical datum, and tidal parameters used for corrections. Taking all these factors into account required specific data processing, hardware and software strategies.

For comments and questions, contact Rich Signell



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