Problems with the shoreline development index - a widely used metric of
lake shape
Abstract
The shoreline development index - the ratio of a lake’s shore length to
the circumference of a circle with the lake’s area - is a core metric of
lake morphometry used in Earth and planetary sciences. In this paper, we
demonstrate that the shoreline development index is scale-dependent and
cannot be used to compare lakes with different areas. We show that large
lakes will have higher shoreline development index measurements than
smaller lakes of the same characteristic shape, even when mapped at the
same scale. Specifically, the shoreline development index increases by
about 14% for each doubling of lake area. These results call into
question a wide variety of previously reported patterns and
relationships. We provide several suggestions to improve the application
of this index, including a bias-corrected formulation for comparing
lakes with different surface areas.