Instructor Materials: Overview of Analyzing High Resolution Topography Module

Module Goals

Students will be able to:

  1. Design and conduct a complex TLS and/or SfM survey to address a geologic research question.
  2. Articulate the societal impetus for answering a given research question.
  3. Justify why TLS and/or SfM is the appropriate method in some circumstances (if both methods are used).

Summative Assessment

The Summative Assessment, Unit 5, is the final unit of the module. The exercise evaluates students' skills in survey design, survey execution, and simple data exploration. As this is not designed to test any specific geologic context, we include a number of potential study topics with associated questions and prepared data sets for courses not able to collect data in the field. Learn more about assessing student learning in this module.

Outline

The module covers material sequentially, but the units can also often be taught as stand-alone lessons. For instructors who do not wish to use the module in its entirety, suggested pairings are included in the "Context for Use" section on each unit's page. Instructors can request support for some types of technical assistance from UNAVCO, which runs NSF's Geodetic Facility.

Unit 1-TLSIntroduction to TLS

This unit introduces students to the technical aspects of terrestrial laser scanning (TLS) survey design and execution. TLS requires a range of equipment, careful planning, and many hours of scanning in order to complete a successful survey, but it yields a high resolution topographic model valuable for addressing a range of geologic research questions. This unit is designed to be used as an alternative to or concurrently with Unit 1-SfM.

Unit 1-SfMIntroduction to SfM Photogrammetry

This unit introduces students to the technical aspects of Structure from Motion (SfM) photogrammetry survey design and execution. SfM requires less expensive equipment and less field time but more processing time than TLS. In low-vegetation field areas, it can yield a similarly valuable high resolution topographic model applicable to a variety of geologic research questions. Software for SfM varies; the unit was written to work with Agisoft Photoscan Pro but suggestions for open-source alternatives are given in the instructor overview. This unit is designed to be used as an alternative to or concurrently with Unit 1-TLS.

Unit 2Geodetic survey of an outcrop for stratigraphic analysis

Geodetic surveying techniques have many applications in sedimentology research, including lithological identification and analysis, sediment surface topography, and sequence stratigraphy. In this unit, students will design a survey of a geologic outcrop to conduct a sequence stratigraphy analysis. The goal is to calculate deposition duration and sedimentation rate based on thicknesses extracted from the data. Students tie these analyses back to societally important issues such as climatic change and energy extraction.

Unit 3Geodetic Survey of a Fault Scarp

Fault scarps are the topographic evidence of earthquakes large and shallow enough to break the ground surface, and are evidence of Quaternary fault activity. In this unit, students will design a survey of a fault scarp. The goal is to create a brief report summarizing the methods used and Quaternary history of displacements on the fault and thus its potential earthquake hazard. This unit also includes an additional optional exercise in data processing. Students will transform a point cloud into a DEM. Then students will be able to extract profiles of the scarp using ArcGIS and import these profiles into MATLAB to conduct hillslope diffusion analysis.

Unit 4Geodetic Survey for Geomorphic Change Detection

One major application of geodetic surveying techniques in geoscience research is quantifying change in geomorphological settings, such as a fluvial system, forest fire, landslide, or any other erosional features. This is done by finding the difference between georeferenced repeat data sets. Students will learn to clean up the data, remove vegetation, transform the point cloud to a DEM, and then compare that DEM to a previously collected data set to quantify change.

Unit 5Analyzing High Resolution Topography Summative Assessment

Unit 5 is a final exercise and evaluates students' skills in survey design, survey execution, and simple data exploration and analysis. Unit 5 is the summative assessment for the module. As this is not designed to test any specific geologic context, we include a number of potential study topics with associated questions and prepared data sets for courses not able to collect data in the field.

Making the Module Work

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