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TCM Bathy Blog

  • Welcome to TCM’s Bathymetry Blog, where we will talk about what is happening at TCM, and also about interesting topics that relate to the world under the sea. Our latest news is the completion of TCM’s global vector coastline. It’s taken us more than five years to trace-mostly by hand-a 1:50,000 scale coastline derived from Landsat imagery, and it is finally complete. This coastline is the most accurate, most detailed, and most nearly complete world coastline data set available from either public or commercial sources.

    We are now able to offer a 1:50,000 scale vector data set that captures more than 2,000,000 linear km of coastline and includes more than 300,000 islands. (If two million km of coastline sounds like an unbelievable number, follow this link to understand the fascinating reason why it’s not: See also the Richardson Effect.)


    Why spend so much time and effort to create a world coastline? The coastline is the zero-elevation contour line, the nexus of the terrestrial and marine worlds, and thus the elevation against which all other measurements on land and under the sea are based. Since all elevation values are related to height above or below sea-level, all of those values are just approximations without an accurate coastline.

    Borneo Coastline

    Borneo Coastline