Module 2.1 - TINs and DEMs

This week's laboratory assignment covered the inputs, differences, and uses for DEMs (Digital Elevation Models) and TINS (Triangulated Irregular Networks). I often use these two topographical representations in projects and find them to both have their own pros and cons. This particular lab showcased that they are both fairly different and should be used based on what type of data is being shown and how it should be represented. I enjoyed learning about the differences between the two through a variety of spatial tools and analyses.

Personalized TIN Symbology

My analysis of TINS and DEMs proved to me that TINS are often superior to the standard DEM in many ways. TINS often do not generalize as much as DEMS, and showcase more data in areas that have higher densities of data. For example, the TINS generated contour lines were much more accurate and forming to the terrain present in part D of the assignment. TINS are generated from vector point data that contain x, y, and z coordinates and bind together three points of differing relief to generate a triangle. This triangle is compiled with multiple others to showcase topographical data in a unique way that is dissimilar to many other elevation data representations methods.

Contour Lines Derived from TINS vs DEMS

While the general area in which the contour lines resided on the map were generally the same or fairly close, there was a key difference between the two sets of contour lines that stood out. When viewed from a straight-down aerial view, contour lines for the original TIN image created using the symbology features were sharper and more jagged, while the contour lines created from the DEM using the contour tool were more round and smooth. The differences are most noticeable in areas where the terrain bends and is least noticeable in long stretches of similar terrain. This is likely because the two methods of acquiring the contours were different, with one deriving them from the TIN (triangulated vertices) and other from the created DEM. I would think the contours representing the TIN layer are more accurate, as they are not generalized/rounded and are better at showing areas of relief. When the contour lines are viewed at an eye-level perspective, one may notice that the TIN derived contours better align with the natural landscape than the DEM contours, which appear distorted.

 

Original TIN File

Modified TIN Layer

ArcGIS Pro allows the user to modify the symbology of a TIN Layer to meet the needs of the user or client. I enjoyed working through the symbology to show where Bear Lake lies in terms of the surrounding landscape. Through adjusting the surface to showcase slope data and adding edges, one may better visualize Bear Lake and the terrain it is bordered by. I believe TINS are much more accurate than a general DEM in this case, as the terrain is very dense in this region and it is important to not dissolve edges in cases like these.