Accuracy and User Variation Associated with Slope Measurement Using a Laser Hypsometer

Abstract

Slope measurements are often necessary for assessing features and processes within the natural environment. Land managers often use handheld equipment rather than more complicated surveying equipment in order to measure slopes and to conduct field work efficiently. One type of handheld device used to measure slope is a laser clinometer. In order to determine the accuracy and user error associated with this type of clinometer, slope measurements were taken at multiple locations using two types of equipment: 1) a Haglof Sweden Vertex III Hypsometer with a laser clinometer function and 2) a Topcon GTS-603/AF electronic survey total station which can measure elevations and distances to an accuracy of ± 2mm. Slope measurements were compared among the four Vertex III clinometer users in order to determine the variation associated with each user. Also slopes determined by the clinometer were compared to those determined by Topcon GTS-603/AF in order to assess the accuracy of the clinometer. Slopes measured by the laser clinometer users were not significantly different (=0.05) than those measured using the total station, and the differences on average between the laser clinometer and the total station slopes were less than one percent slope for all clinometer observers.