Topographic analysis of the Sangre de Cristo Range -- GIS Project

Eric Leonard, Colorado College - Geology Department

Summary

Students make DEM-based observations and develop and test hypotheses regarding topographic differences between the two sides of the Colorado Sangre de Cristo Range.

Context

Type and level of course
Required undergraduate course in geomorphology (300-level)

Geoscience background assumed in this assignment
Project assumes that student has a general familiarity with geomorphology, especially with tectonic, fluvial, and glacial geomorphology.

GIS/remote sensing skills/background assumed in this assignment
Project assumes that students have completed an introductory GIS lab that has given them a basic introduction to the ARC Map interface, file management, and to basic functions in Spatial Analyst.

Software required for this assignment/activity:
At least -- ARC-GIS 9.2 with Spatial Analyst extension, Excel

Time required for students to complete the assignment:
Two three-hour labs sessions plus evening write-up time.

Goals

GIS/remote sensing techniques students learn in this assignment
Increased familiarity with capabilities of ARC GIS. Introduce students to more Spatial Analyst functions. Begin to move students away from pure cookbook use of GIS, get them thinking about how they can use Spatial Analyst and raster calculator to try to answer geologically significant questions.

Other content/concepts goals for this activity
Identification and differentiation of fluvially and glacially dominated landscapes via DEM analysis. Identification of indicators of active tectonics in GIS.

Higher order thinking skills goals for this activity
Help students to develop the ability to formulate questions to allow them to make geomorphic inferences from DEMs. Help them to use spatial analysis tools to distinguish between multiple hypotheses of landscape causality.
This project is integrated with the tectonic geomorphology portion of the class – which includes both a general discussion of tectonic geomorphology and more detailed discussion of the Neogene/Quaternary geomorphic evolution of the Colorado Rockies – focusing on discussion of the roles of tectonics and climate in shaping mountain landscapes.

Description of the activity/assignment

Students are given DEM grids of the Colorado Sangre de Cristo Range and bedrock geology and stream profile shape files, along with some general background information on the range. In the lab instructions they are first lead through an initial set of observations about the topography of the two sides of the range – particularly about differences in valley morphology between the two sides, and asked to summarize these observations. They are then introduced to a few additional tools (mostly from Spatial Analyst, but also making use of Excel and MicroDEM, that can provide them with more quantitative observations. Finally, students are asked to generate hypotheses to explain their observations and to turn in a short scientific paper (4-5 pages of text, plus figures) detailing their observations and their explanations of the morphological differences.

Determining whether students have met the goals

Students write individual scientific papers on project. I assess these papers in terms of how well students have made use of the new GIS skills they have (one hopes) acquired and how well that have generated and tested geologic hypothesis from their observations. I have been redesigning the lab almost every year to try to get at these goals more effectively.
More information about assessment tools and techniques.

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