LiDAR Accuracy on North American Mountain Summits

TL;DR

This study evaluates the accuracy of airplane-based LiDAR measurements of mountain summits across North America by comparing them with differential GNSS surveys, revealing typical vertical errors around 0.5 meters and horizontal errors around 2-3 meters.

Contribution

It provides a comprehensive assessment of LiDAR accuracy in complex mountainous terrain using multiple measurement methods and diverse summit types across North America.

Findings

Average vertical error for LiDAR methods was approximately 0.5 meters.

Horizontal errors ranged from about 2.4 to 3.8 meters depending on the method.

Error sources include vegetation, structures, snow/ice, and summit erosion.

Abstract

Mountainous terrain is increasingly being measured and mapped by airplane-based LiDAR (Light Detection and Ranging) techniques, but the accuracy of these measurements in such topographically variable terrain is not well understood. For this study we measured 179 mountain summits with differential GNSS static surveys and compared summit elevation and location measurements to those measured by LiDAR in point cloud data sets. We measured summits in 13 US states (Washington, Idaho, Montana, Utah, California, Nevada, Arizona, New Mexico, Michigan, Wisconsin, Kentucky, Colorado, and Pennsylvania) and two Canadian provinces (British Columbia and Nova Scotia). Summits included icecapped peaks, open rocky peaks, and tree-covered peaks ranging in elevation from 490m to over 4000m. LiDAR-point-cloud-derived summit elevations and locations were computed using four different methods: manual processing, highest ground return, highest return, and Lastools reclassification. The average one-sigma LiDAR vertical errors for each method were 0.50m, 1.09m, 9.83m, and 1.96m, respectively. Average one-sigma horizontal errors were 3.03m, 2.41m, 5.17m, 3.78m, respectively. Errors are also presented separately for each type of summit. Error sources include sharp summits being unsampled, dense vegetation misclassified as ground, human-created structures misclassified as ground, snow/ice that can melt over time, and summit erosion over time.