Module 2.1 - Surfaces - TINs & DEMs

 This module was one of the most intriguing yet in my GIS journey. Instead of the usual lab exercise in which I am given data and expected to use my skills to reach a desired outcome via a series of well-executed processes, I more so was expected to simply engage with data in a manner of ways and learn how surfaces can be represented digitally better. The exercise consisted of 4 distinct steps that I will provide details of my experience about. All data was provided by UWF and utilized in ArcGIS Pro. 

Part A. 

    In this portion of the exercise I learned that TINs and DEMs cannot be seen as three dimensional surfaces inherently. I directly worked with TIN data to explore this further, learning that the TIN itself acts like a blanket covering the surface with visual data. To represent the data three dimensionally, I learned how to create an elevation surface layer from the data in a Local Scene and utilize Vertical Exaggeration to exaggerate the terrain. This allowed me to produce a meaningful three dimensional visual of the surface, all from one set of 2D data.

Part B.

    In this portion of the exercise, I got to interact with DEMs and TINs. The exercise aimed to simulate a ski run suitability map assessment. I learned how to convert a DEM raster to a TIN file so that I could use the TIN as a surface elevation layer. This allowed me to provide three dimensional space to blanket the DEM over. After reclassifying the DEM based on slope, aspect, and elevation, I was to find a way to symbolize the classification based on particular weights for each classification suitability. I opted to use the Weighted Overlay tool, as it seemed to be the most intuitive. I then tinkered with exaggeration values and illumination parameters to visualize the scene in a more real-world manner. I will provide a screen capture of the result here: 

Part C. 

    This portion of the exercise involved exploring TINs a bit more in depth. I looked at how TIN data can be symbolized via points, contours, edges, and surface. I found it interesting how I could symbolize all of these factors simultaneously or individually. I explored the data surface based on both slope and aspect, gave the triangles of the TIN symbolized edges, and developed contour lines. I enjoyed getting comfortable seeing how all these symbolization methods interacted with each other.

Part D.

    This final portion of the exercise prompted me to create my own TINs and DEM's using a feature layer of elevation points. I explored how the elevation points were distributed based on the TIN I created, using the symbolization tactics from Part C to do so. I also created contour lines from my created TIN and DEM and explored the differences between the two. Seeing as elevation points play a much more real, boundary-like role in TINs and an interpolation role in DEMs, the two sets of contours proved to be quite different. While following similar patterns, I got to see how complex areas of surfaces and less complex areas play a big role in how accurate the contours derived from each method are.