The use of airborne LiDAR data and semi-automated GIS tools for the identification and mapping of fluvial terraces along Powder River, Montana
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
This thesis compares river terrace polygons and elevation data from a semi-automated mapping program (TerEx) in ArcGIS to previously collected field-based polygons and elevation data over a 30 km stretch of Powder River’s valley in southeastern Montana. The purpose of this study is to determine if the polygon outputs of the semi-automated program matches with prior field, spatial (e.g. maps), and chronological (e.g. terrace elevations) interpretations. As determined by comparative geometric analyses and field observations, the semi-automated polygons rarely match with prior studies. Spatially, the TerEx program commonly creates too many polygons due to slight elevation differences and segmentations caused by agricultural activity, rough terrain, and roads. In other instances, the program output creates polygons that are too large predominantly in regions directly adjacent to alluvial fans where depositional and erosional processes are acting upon and altering the landscape. Large portions of the TerEx polygons fall within and aid in assessing previously identified chronological terrace elevation parameters. The sum of our data indicates that TerEx is useful in conjunction with extensive prior field-based data, but on its own would provide unreliable results.
Description
Keywords
River terrace, Semi-automated mapping program, Semi-automated polygons, Alluvial fans, Southeastern Montana