This article offers a general introduction to those aspects of bathymetric mapping and satellite altimetry that are relevant to bathymetry from space. We begin with a review of some of the strengths and weaknesses of conventional bathymetric measurement and mapping. This context highlights the case for and value of space-based mapping: it is the only way to achieve globally uniform resolution within reasonable time and cost. However, a space mission cannot “see” the ocean floor directly; instead, it observes gravity anomalies that can be correlated with ocean floor topography. Geological factors and physical laws limit the resolution of this technique to a particular range of spatial scales (~100 km to ~5 km). While this is not perfect, it yields an enormous improvement in the resolution of global bottom roughness over traditional methods (Figure 1).

Smith, W.H.F., and D.T. Sandwell. 2004. Conventional bathymetry, bathymetry from space, and geodetic altimetry. Oceanography 17(1):8–23, https://doi.org/10.5670/oceanog.2004.63.

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