Juneau to Skagway Access Road LiDAR & Orthophotography
The Alaska Department of Transportation and Public Facilities needed to develop three-dimensional modeling of avalanche chutes and the proposed roadway corridor for the Juneau Access Road. AeroMetric provided high-resolution orthophotography, accurate controlled contour mapping, and high-resolution digital elevation model (DEM) data. The avalanche paths were mapped from the accumulation zones along the mountainsides to the run-out zones at the shoreline. This information allowed the Department to identify avalanche mitigation options for each identified path.
This project involved mapping between the end of the existing Glacier Highway at Echo Cove, approximately 39 miles north of Juneau, Alaska (by road), and 4-miles north of the town of Skagway, Alaska, approximately 64 miles farther to the north. The proposed roadway corridor crossed Berners Bay and proceeded up the east side of Lynn Canal, crossing the Katzehin River before reaching Skagway. Approximately 59 avalanche chutes were identified in the area ranging in size from large or larger than the Thane avalanche chute just south of Juneau. The route generally followed the shoreline. The terrain is mountainous with elevations ranging from sea level to over 2000-feet above sea level on the proposed route, and as high as 5500-feet at the head of some of the avalanche areas. There were numerous smaller stream crossings and the route was heavily forested with Hemlock, Spruce and Alder trees.
Orthophotography at 1”=1500’ (1.5 foot pixel resolution) and Light Detection and Ranging (LiDAR) proved to be an excellent tool for this application. The LiDAR was able to penetrate between the conifers to measure ground elevations suitable to meet project specifications. Data was obtained using an Optec 2025 system. The sensor configuration included an Airborne GPS receiver as well as the Applanix POS/DG Inertial Measuring Unit (IMU). These exacting positioning systems provided precise sensor locations and orientations necessary to derive the digital elevation models relative to real world coordinates resulting in data accuracies that met and in some cases exceeded project specifications.
West Lynn Canal Orthophotography and LiDAR Project 
