GIS5100 Module 2: Forestry & LiDAR

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Light Detection and Ranging (LiDAR) is a powerful remote sensing technology that enables us to map the world more precisely with high-resolution models. It is also this week's Module topic! I'm not new to LiDAR or to working with LiDAR/DEMs; however, the application we do is different from what I experienced in Module 2, which is great! I love the variety and change of pace. It really goes to show how versatile GIS is.

This week, we find ourselves in Virginia, specifically Shenandoah National Park. It is there that we're given a file geodatabase with Virginia boundaries in polygon and polyline form, as well as a LAZ file, which is a compressed version of LiDAR point cloud data. I immediately learned that LAZ files are not readable in ArcGIS Pro, while LAS files are. After some trial and error, I realized I didn't need to run the Convert LAS tool on the provided data, since it was already in the proper format for ArcPro to read. Simply misunderstood the instructions that stated you can skip certain steps. If you downloaded straight from the Virginia LiDAR Download website, then you'd need to convert from LAZ to LAS.

The bulk of the lab involved extensive geoprocessing using various tools. After retrieving the data from the provided data folder or the Virginia LiDAR site, we then went into Calculating Forest Height, where we created a DEM and DSM that depicted the range of tree heights. I often download DEMs directly from USGS, so being able to see how to derive DEMs and DSMs from LAS data is cool. Which reminds me, having the LAS Points setting (All Points, Ground, Non Ground) is crucial when converting and running the the LAS Dataset to Raster tool. If you run it with the wrong LAS Point setting, you may end up missing some data values or pixel coverage in your raster tile.

Next, the lab required us to Calculate Biomass Density. This one required the most geoprocessing tools: LAS to MultiPoint, Point to Raster, Is Null, Con, Plus, Float, and Divide. It was very important to keep my settings straight and follow the instructions to a "T". Inputting the wrong thing could set you back, and you'd have to re-run the tools possibly from the beginning.

Once those two processes were complete, we were finally able to create 3 layouts based on Forest Tree Height Map/Chart, Canopy Density, and LiDAR and DEM or DSM. I had fun getting back into the swing of making layouts, especially after the programming course. I just love seeing what creative things I can do with them. Feel free to view them below.

Tree Height Map. It shows the 2014 vegetation heights of this area of Shenandoah National Park. Darker blue indicates shorter vegetation, greens are middle ranged, and yellows are the tallest.

Canopy Density Map. It shows the 2014 canopy density of this area of Shenandoah National Park. In this case, yellow (0 values) indicates lower density, and darker blue (1 values) indicates greater canopy density.

LiDAR & DEM Map. It shows the 2014 LiDAR Point Cloud and DEM of this area of Shenandoah National Park. Due to the 3D Scene, a scale cage polygon feature was created for the LAS Point Cloud map frame to act as a scale bar.

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