Improving 3D Spatial Visualization of Stream Channel Morphology: A Geomorphic Application of ArcView 3D Analyst Extension.
John Van Hoesen Green Mountain College
This is a partially developed activity description. It is included in the collection
because it contains ideas useful for teaching even though it is incomplete.
This laboratory exercise helps student bridge the gap between fieldwork, data collection, visualization, and interpretation of the data. Using a combination of surveying techniques, spreadsheet modeling, and GIS , students further develop their spatial visualization skills and use these skills to predict geomorphic responses.
GSA Poster (Acrobat (PDF) 1.4MB Oct31 03)
Higher Order Thinking Skills:
Using the survey data collected along the stream/river, students are encouraged to "predict" what the morphology of the stream will look like under varying conditions. They are then asked to develop arguments to defend their predictions.
Reinforcement of skills relating to data collection with a total station, surveying techniques, and graphing data.
This exercise has only been used in an undergraduate Geomorphology course.
The students must have a working understanding of traditional graphing techniques (graph paper), and Microsoft Excel (or equivalent). They should at the very least be familiar with surveying equipment (either a total station or transit) as well as GIS.
Role of Activity in a Course:
I introduce this exercise as part of a sequence of exercises. I begin with an exercise in traditional terrain analysis description of topographic maps, the second lab utilizes the same topographic maps in digital format within a GIS. Students are asked more questions and then using the 3D analyst, they evaluate they own answers by "extruding" the topography to further enhance their visualization skills.
Data, Tools and Logistics
A computer lab with sufficient GIS packages, surveying equipment (total station, transit, waders, measuring tape, compass, etc), GPS, and a graphing program.
Most of these are readily available in most departments, however the instructor should have some understanding of ArcView or ArcGIS for this to be a successful exercise.
Some students will not have had sufficient training in either surveying techniques or GIS applications. As with any field-based exercise, weather is always a logistical challenge.
I would like students to (1) strengthen their spatial visualization skills through repetitive use, (2) be able to envision the cross-sectional morphology of streams and rivers both with and without graphing, and (3) predict how this morphology changes in response to geomorphic processes.
Evaluation is currently based on the quality of the stream morphology predictions students make after the 3D visualization, versus the predictions they make prior to the GIS component of the lab. However, actually assessing the "amount" of improvement in spatial analysis has so far been problematic.
Students spend one laboratory session collecting topographic data along stream channel cross-sections. Using this data, they are asked to construct 2-dimensional cross sections both by hand and in Microsoft Excel. They are then asked to sketch the shape of the cross-section after urbanization, flooding events, changes in baselevel, etc, between laboratory sessions. During the second week, they are asked to create and manipulate 3-dimensional models of the stream channel using their survey data. They are presented with the same questions and asked to re-evaluate their original sketches.