Thesis
On computing generalized watershed boundaries of polygonal regions in digital elevation models
Bachelor of Science (B.S.), Drexel University
May 2020
DOI:
https://doi.org/10.17918/00001056
Abstract
Flow Direction Grids (FDGs) are commonly used to describe the effects of fluvial systems on the watershed or the local stream reach. We propose a novel alternative approach that captures all FDG cells within a surface flow distance that is less than or greater than a user-defined threshold. Existing techniques for identifying constrained watershed boundaries require manual computations that run in quadratic complexity as a function of the number of cells on their boundary. Our research describes a computational model to identify and retrieve watershed boundaries for arbitrary simple geometries where flow can be constrained by a user-defined threshold. Specifically, we propose a linear-time algorithm with respect to the length of the output geometric boundary to identify and retrieve constrained watershed boundaries for any query region. This algorithm leverages a novel data structure, the Constrained Modified Interval Search Tree.
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Details
- Title
- On computing generalized watershed boundaries of polygonal regions in digital elevation models
- Creators
- Daniel Ethan Schwartz
- Contributors
- Ali Shokoufandeh (Advisor) - Drexel University, Computer Science
- Awarding Institution
- Drexel University
- Degree Awarded
- Bachelor of Science (B.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- vii, 29 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Computer Science (Computing) (2013-2026); College of Computing and Informatics (2013-2026); Drexel University
- Other Identifier
- 991018526906204721