Applications Module 2

 

Module 2 

Biomass Density from LiDAR Imaging in the 

Shenandoah Nation Park in Virginia

In this module the importance of following directions carefully was reinforced to a considerable degree as I had to make multiple attempts at creating a desired finished raster file called Canopy Density that would be included in my layout at the end.

    In the first steps of the module I ran into some issues with the downloaded file from the Canvas link. For some reason when I attempted to create the .lasd file using the Point File Information tool, the created .lasd file contained no information or georeferencing information. Continuing with my first attempt the LAS Data to Raster tool ran as it should but I did not catch the part that mentions inserting a New Local Scene in a previous step so I continued to work within the regular map scene.

Another step instructs to navigate to the LiDAR layer (at this point I have only very lightly worked with LiDAR layers from a previous course) and did not understand that the lab instruction was directing me towards the original .LASD file that was previously created. This instruction wanted me to change the “LAS points to Gound”.
            I’m assuming that the “gound” meant to say “ground” as this was a bit of a struggle to decipher where I needed to find the option to change the points to ground but eventually studied some of the images that accompanied the texts.

    I think it would have been helpful to reference the input and output files for this module by their file name as this is where my issues began. After creating the DSM and DEM I calculated the height raster. One of the lab instructions notates that if there are any negative values that result in running the minus tool that would mean they are an error. However, it does not go on to tell me that those errors need to be addressed before moving on so I continued onto the next steps calculating biomass density.

            Iterating through the processes of running each geoprocessing tool I found it very important to be precise when naming the data file names as there were over a dozen files created in this lab which can be easily lost if they are not documented correctly.

            After creating the “Canopy Density” raster (now on the second attempt) I sifted through the different symbology options and settled on one that resembles the map example included in the lab as it set apart the lowest elevations from the highest.

    I then created a chart histogram of the values of the canopy heights and saved it as an image. I did this because I’ve found that adding image files to a layout is much easier than using some of the tools to import it directly from the layout options. I set a background color to the layout as an alternative to a pure white background that felt easier to look at. (I don’t care to stare at documents that are so formal that it feels like I’m reading the white papers to a doctoral thesis).

            After adding all the map elements like scale bar and north arrow, I adjusted the map view in the layout in a way that helped accentuate the 3D model of the canopy grid.