Diff. between waterlining and Boggs' method


The fully-automated waterlining method is illustrated in the top figure, in which the density of waterlines, for clarity's sake, is half of what was used to derive the median line (in black) between states A and B. All the method needs is an ordered list of shoreline coordinates, plus project parameters such as the said density. The precision of the result, a direct consequence of that density, entirely depends on the user. The computations develop, also subject to the user's wishes, on a projection plane, a sphere, or an ellipsoid. Those modest requirements underlie the automated character of the waterlining method and, therefore, the invulnerability of its results to claims of bias.
      Waterlining also provides automated, bias-free solutions for problems such as the closing of bays and the delimitation of median lines when a "half-effect" is sought in cases of multiple states, island states included.
      The bottom figure illustrates one manner of practicing Boggs' method for the tracing of median lines. Another manner requires the tracing of arcs of circles. We excluded it because it leads to a more confusing picture.
      The method, either as in the original proposal by S. W. Boggs, then (1930) Geographer of the U.S. Department of State, or in today's popular semi-automated approaches, demands the manual selection of characteristics points (red in the picture) in the opposite shorelines. Boggs's idea was brilliant, and that shows in the simplicity and elegance of the illustration on the left. However, in a sense, that picture is deceptive, for the user must know beforehand where the limit should be, in order to select the red points and to find the turning points (yellow in the picture). Moreover, some of the approaches necessitate a selection and threading of those turning points into the final median line.
      The line we drew between points 1 and 2 represents a straight baseline. To avoid supposed complexities in sea limits and also to protect the rights of states to the so-called historic bays, it is possible to invoke the principle of Straight Baselines in order to close with straight lines the shoreline sections in question. In reality, between Straight Baselines and the lines that join consecutive points in Boggs' method there are only conceptual differences. So much that, in practical terms, we could very well say that Boggs' method is based on the acceptance of a principle of mini Straight-Baselines.