Module 2.1 of Special Topics in GIS was based on surfaces, particularly Triangulated Irregular Networks [TINs] and Digital Elevation Models [DEMs]. The first portion of the lab was an opportunity to import elevation data, set the ground source [giving it 3D visualization], and learning how to exaggerate the vertical distances to enhance the visual aesthetics of the landscape. Once these fundamental concepts were practiced, an analytical problem was presented.
The second portion of the lab was to create a Suitability Map for a study area that illustrates the best locations for a ski resort and its associated ski run. The suitability was determined based on slope, elevation, and aspect [directional face] of the landscape. The dark green areas of the map below display the most suitable locations of the resort, and the red areas signify areas that are unsuitable for this tourist destination.
The final portion of this lab dealt with TIN's and DEM's. Environmental Systems Research Institute [ESRI] defines a Triangulated Irregular Network as a form of vector-based digital geographic data and are constructed by triangulating a set of vertices [points]. The vertices are connected with a series of edges to form a network of triangles.' The documentation for this model type is quite extensive, and can be found by clicking here. Furthermore, ESRI defines Digital Elevation Models as 'a raster representation of a continuous surface, usually referencing the surface of the earth' [ESRI, 2024]; the complete documentation for DEM's can be found by clicking here. Once these two models were created, contour lines were derived at 100 meter increments [see map below]. Contours represent lines of equal elevation that are spaced at equal intervals [Bolstad & Manson, 2022].
Due to the data types of the models used to create the contour lines, the output of each varies in appearance. Since TIN's are based on points, lines, and polygons, the contour lines take on a very segmented appearance. Conversely, a raster-based DEM will create contour lines with a very transitional and organic aesthetic.
Sources:
Bolstad, Paul & Manson, Steven. (2022). GIS Fundamentals: A First Text on Geographic Information Systems (7th Edition). Eider Press.
Environmental Systems Research Institute. (2024). Exploring Digital Elevation Models.
Environmental Systems Research Institute. (2024). What is a TIN Surface?
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