Christa's GIS Archive

Halfway through the course, we reach Module 2.1, which focuses on TINs & DEMs. While I mainly use DEMs in my work, this lab was a great opportunity to become more familiar with Triangulated Irregular Networks (TINs) and how they convey elevation. As a refresher, a "triangulated irregular network (TIN) is a data model commonly used to represent terrain heights" (Bolstad & Manson, 2022, p. 61). Our lab uses both TINs and DEMs to address elevation in California's Death Valley in a four-part series. In Part A, we used the Death Valley TIN as an elevation source, then overlaid a radar image on it with some vertical exaggeration. This allowed us to get used to working with both 2D and 3D spaces. Screenshot of Part A TIN and radar image overlay. From there, we delved deeper into 3D applications in Part B, where we assessed ski run suitability using elevation, slope, and aspect rasters. We used a starting DEM to create the TIN for the 3D elevation surface, as well as the ...

A long weekend this week has been a nice way to catch up on several things in life, and makes staying on track in this course a little more easier. Speaking of long, this week was all about assessing road network quality through completeness. Now, how were road networks deemed complete? Well, we went at lengths for that. Literally! Haha. Using a similar approach to the Haklay (2010) study, we compared two road networks, TIGER Roads and Street Centerlines, in Jackson County, Oregon by their total lengths in kilometers. Throughout the entire Jackson County, it was found that the TIGER Roads network had a longer length of roads than the Street Centerlines network, specifically 576.9km more. As mentioned in Haklay's study, completeness was deemed by Van Oort as the "comprehensive... coverage of real-world objects" (Haklay, 2010, p. 685). In our case, we analyzed further than just total lengths alone to get a full understanding of road network completeness. Like in Haklay...