The new Digital Terrain Model (DTM) of the Brazilian Continental Margin: detailed morphology and revised undersea feature names

The Digital Terrain Model was developed based on all available bathymetric data, already processed and validated. The SRTM30_PLUS (Shuttle Radar Topography Mission) data were used just to complement the bathymetric grid in distal regions of the Brazilian Continental Margin.

In order to prepare the bathymetric grid from a database composed by all qualified bathymetric information, it was adopted the Randgrid.GX/Geosoft - Oasis Montaj®, version 9.5.2, routine. The used mathematical model creates a surface of minimum curvature, using a similar method to that proposed by Swain (1976) and Briggs (1974), with the interpolation, in each knot of the grid, of X and Y values in metric coordinates and Z values (variable). The calculated surface adjusts itself to the irregularly sampled original values. The grid cell-size was 1,000 m, defined according the spatial distribution of the available data.

The Brazilian DTM Oasis grid file was converted to surfer files, Versions V6 and V7. The ASCII file and a Geotif image were also provided. The reference system and geodetic datum adopted for the bathymetric data was the WGS84. The projection adopted was the World Mercator (false N=0, false E=0, latitude of the natural origin=0 longitude of the natural origin=0, and the scaling factor of the natural origin=1).