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The seamount geomorphic feature layer represents the spatial extent of the seamounts of the worlds oceans based on interpretation of the SRTM30 plus v7 global bathymetry model. The layer is one of the 25 layers that make up the global seafloor geomorphic features map (Harris et.al. 2014). Seamounts are “a discrete (or group of) large isolated elevation(s), greater than 1,000 m in relief above the sea floor, characteristically of conical form” (IHO, 2008). Seamounts are thus defined as peaks that rise over 1,000 m above the seafloor, calculated based on the SRTM30_PLUS model. We adhered strictly to the requirement that seamounts are “of conical form”, thus distinguishing “seamounts” (having a length/with ratio <2) from ridges (having a length/width ratio ≥2). The criterion of a length/with ratio <2 for seamounts is consistent with the geomorphic analysis of Mitchell (2001). Seamounts are, furthermore, distinguished from flat-topped guyots.
The ridge geomorphic feature layer represents the spatial extent of the ridges of the worlds oceans based on interpretation of the SRTM30 plus v7 global bathymetry model. The layer is one of the 25 layers that make up the global seafloor geomorphic features map (Harris et.al. 2014). Ridges in this study are confined to “an isolated (or group of) elongated narrow elevation(s) of varying complexity having steep sides, often separating basin features” (IHO 2008). In this study “ridges” were confined to features greater than 1,000 m in relief and do not include the mid-ocean ridges, which was mapped as a separate feature.