Summary

Description

In support of geologic mapping and hazards evaluation in and near Whittier, Alaska, the Division of Geological and Geophysical Surveys (DGGS) acquired, and is making publicly available, lidar (light detection and ranging) data for an area along Passage Canal, Portage Lake, and Portage Glacier Highway. The lidar data, acquired between 21 - Oct 25 2013, was processed by Watershed Sciences, Inc. (WSI) and consists of continuous coverage encompassing an area extending from Portage Lake eastward to Logging Company Bay in Passage Canal in the Seward D-4, D-5, and D-6 1:63,360-scale quadrangles. Lidar data collected below 1,600 ft (488 m) elevation have a minimum average pulse density of 8 pulses/square meter; above 1,600 ft (488 m) data were collected with an average pulse density of at least 4 pulses/square meter. Following lidar data collection and processing by WSI and their survey subcontractor, McClintock Land Associates, WSI submitted the data to the State of Oregon Department of Geology and Mineral Industries (DOGAMI) for independent quality control analysis. After addressing any concerns from DOGAMI, WSI submitted the revised dataset to DGGS along with a technical report describing details about the lidar acquisition, accuracy, and quality. DOGAMI also provided a separate report summarizing their methodologies and the results of quality control checks. The following data classifications are available for download from the NOAA Digital Coast: 1 (Unclassified) 2 (Ground) 3 (Low Vegetation) 4 (Medium Vegetation) 6 (Buildings) 7 (Low Point/Noise) 9 (Water Surface) 10 (Ignored Ground - Ground points within 1 m of breaklines) 14 (Withheld - Points that have intensity values of 0 or 255) 15 (Mobile - Temporary Placed Structures (cars, boats, docks, buoys)) 16 (Utilities - Man made non-habitable structures (fences, power lines))