TY - JOUR
T1 - An algorithm to reduce a river network or other graph-like polygon to a set of lines
AU - Schaefer, E. I.
AU - Pelletier, J. D.
N1 - Funding Information: This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1143953 . Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The National Science Foundation was not involved with the design or execution of the study, writing of this manuscript, or the decision to submit. We thank Tamlin Pavelsky and an anonymous reviewer for helpful comments that improved this manuscript. Publisher Copyright: © 2020 Elsevier Ltd
PY - 2020/12
Y1 - 2020/12
N2 - In many geomorphic applications, it is necessary to reduce a polygon to a set of axial lines. For example, consider a fluvial channel network. On the one hand, this network has a polygonal footprint with reaches of finite width organized into a branching network. On the other hand, measuring the length or sinuosity of these reaches, as examples, requires the reduction of their polygonal footprints to axial lines. Here we present a new algorithm that can objectively reduce a polygon to such a set of axial lines, formally called a skeleton. Across four illustrative test cases, we show that this vector-based algorithm has some advantages over three raster-based algorithms in current geomorphic use because it generates smooth, continuous, well-centered skeletons and supports a useful scale-independent metric for the removal of spurious portions. Skeletons in this algorithm are uniquely constructed using a minimum of two parameters: a sampling interval (similar to a resolution) and a numeric pruning criterion (which determines skeleton complexity). We have implemented the algorithm as a freely available, open-source, GIS-ready Python code package without commercial dependency.
AB - In many geomorphic applications, it is necessary to reduce a polygon to a set of axial lines. For example, consider a fluvial channel network. On the one hand, this network has a polygonal footprint with reaches of finite width organized into a branching network. On the other hand, measuring the length or sinuosity of these reaches, as examples, requires the reduction of their polygonal footprints to axial lines. Here we present a new algorithm that can objectively reduce a polygon to such a set of axial lines, formally called a skeleton. Across four illustrative test cases, we show that this vector-based algorithm has some advantages over three raster-based algorithms in current geomorphic use because it generates smooth, continuous, well-centered skeletons and supports a useful scale-independent metric for the removal of spurious portions. Skeletons in this algorithm are uniquely constructed using a minimum of two parameters: a sampling interval (similar to a resolution) and a numeric pruning criterion (which determines skeleton complexity). We have implemented the algorithm as a freely available, open-source, GIS-ready Python code package without commercial dependency.
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U2 - 10.1016/j.cageo.2020.104554
DO - 10.1016/j.cageo.2020.104554
M3 - Article
SN - 0098-3004
VL - 145
JO - Computers and Geosciences
JF - Computers and Geosciences
M1 - 104554
ER -