Sawyer Mill Dam Removal Drone DSM Elevation vs. Conventional Survey Terrain Analysis for Reservoir Response Paper (2019 & 2020)

These are the calculations used for examining elevation differences between the drone DSMs and conventional survey elevations across terrain types in the Evans et al. Sawyer Mill dam removal reservoir response manuscript. The “Extract Values to Points” tool in ArcGIS Pro extracted the DSM raster values at the XY locations of the surveyed points. Using the surveyed elevations and extracted DSM values across the available areas and flight dates, trends in the drone DSMs’ Z-direction accuracy were examined across different terrain categories: vegetation, dry terrain (e.g. exposed ground or wood), and submerged terrain (e.g. substrate). Elevation values correspond to NAVD88 in meters. The DSMs' and surveyed points' XY were in WGS 84 when used in the “Extract Values to Points” tool. The "Terrain" columns designate the final terrain type categories used in the terrain analysis presented in the manuscript, while the "Terrain/Notes from Field" columns contain transcribed notes from survey field notebooks that were written in the field. Vegetation heights were also from survey field notebooks. Please see the manuscript and spreadsheet for additional information. <br>These materials were made using resources from an NSF EPSCoR funded project “RII Track-2 FEC: Strengthening the scientific basis for decision-making about dams: Multi-scale, coupled-systems research on ecological, social, and economic trade-offs” (a.k.a. "Future of Dams"). Support for this project is provided by the National Science Foundation’s Research Infrastructure Improvement NSF #IIA-1539071. 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.<br>