Rating is available when the video has been rented.
This feature is not available right now. Please try again later.
Published on Jul 17, 2013
At Black Hawk Creek in Sunderbruch Park a group of students and faculty involved in the St. Ambrose University Summer Research Institute investigated five cost-effective methods of generating stream outlines. Accurately characterizing the outline of a stream is important for many purposes, including recording measurement and sampling locations, monitoring change due to erosion or volumetric discharge, and spatial modeling of stream processes. While expensive surveying equipment or high resolution aerial photography can be used to obtain this data, our research focused on evaluating inexpensive alternatives. In this video (1)the banks were mapped using the GPS feature in consumer-grade digital cameras. (2) We built a point-cloud using multi-view stereo software. We developed procedures for two direct measurement methods, (3) cross-sectional and (4) triangulation. In the cross-sectional method cross-sections were measured at even increments perpendicular to a line of poles placed in the center of the stream. In the triangulation method the distance from two poles to the bank was measured. We also developed (5) the square method, which was a novel photogrammetric procedure which involved floating a large wooden square on the creek, photographing the square and banks from as many angles as possible and then using the square to correct for perspective and extract the outline. While several methods had a small amount of error, our results led us to recommend the square method as an inexpensive method to obtain a fine resolution outline without disturbing the stream environment.