Automated Bedform Identification - A Meta-Analysis of Current Methods
and the Heterogeneity of their Outputs
Abstract
Ongoing efforts to characterize underwater dunes have led to a
considerable number of freely available tools that identify these
bedforms in a (semi-)automated way. However, these tools differ with
regard to their research focus and appear to produce results that are
far from unequivocal. We scrutinize this assumption by comparing the
results of five recently published dune identification tools in a
comprehensive meta-analysis. Specifically, we analyse dune populations
identified in three bathymetries under diverse flow conditions and
compare the resulting dune characteristics in a quantitative manner.
Besides the impact of underlying definitions, it is shown that the main
heterogeneity arises from the consideration of a secondary dune scale,
which has a significant influence on statistical distributions. Based on
the quantitative results, we discuss the individual strengths and
limitations of each algorithm, with the aim of outlining adequate fields
of application. Yet, the concerted bedform analysis and subsequent
combination of results have another benefit: the creation of a
benchmarking data set which is inherently less biased by individual
focus and therefore a valuable instrument for future validations.
Nevertheless, it is apparent that the available tools are still very
specific and that end-users would profit by their merging into a
universal and modular toolbox.