Creating a Digital Terrain Model (DTM) using state-wide LiDAR data project files in ArcGIS Pro8/12/2019
Methods Once the study area was defined as the boundary of the McCormick Wood lot in West Lafayette, IN shown in figure 2, the LiDAR data files covering the study area were downloaded (figures 3, 4, and 5). The files were downloaded into a process-specific folder which was then navigated to in ArcGIS Pro. From there, the files were dragged into the map frame and displayed against a basemap. This ensured that the correct files were downloaded (figures 6 and 7). The next step was to create an LAS Dataset with the LiDAR files; essentially meshing all of the .las files into one (figure 8).
Upon creating the LAS Dataset, the file was displayed in the map frame. The resulting LAS Dataset contains multiple LiDAR pulse returns. These include "first return"- which is used for canopy modeling or "Digital Surface Models" (DSMs), multiple non-ground returns, and "last return", or "ground", which is the final pulse return that was received by the sensor. To create a DTM, the last return was used by selecting "ground" in the LAS Filters tab for the LAS Dataset file (figure 9).
Results In figure 11, the elevation of the McCormick wood lot varies by 46.5 ft over 40 acres. Relative to the difference of 135.5 ft across the 5,800 acre extent of the dataset, the relief of the study area changes more than its surrounding area. In terms of achieving accuracy in future McCormick Woods analyses, whether it be calculating biomass or geocorrecting image products, having a bare earth elevation model to a resolution of 1-ft per pixel will undoubtedly enhance the accuracy of the resulting products.
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Zach MillerWelcome to my field blog! Here you will find the latest updates on what geospatial projects I'm working on. I also provide in-depth workflows and explainations of how I use different functions in various GIS and UAS software to create deliverables. Have a look around by using the categories side bar or just scroll through. ArchivesCategories |