Product: QL1 LAS 1.4
Geographic Extent: This NIR Lidar dataset and derived products encompass an area covering approximately 473,860 acres of South East Alaska. The Quality Level 1 (QL1) project area encompased 130,339 acres of the total area.
Dataset Description :The Glacier Bay 3DEP Lidar project called for the planning, acquisition, and processing of Lidar data collected at an aggregate nominal pulse spacing (ANPS) of 0.31 meters for all QL1 areas. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3. The data was developed based on the NAD83(2011) horizontal datum and NAVD88 (GEOID12B) vertical datum. Data was projected in UTM Zone 8N. All units are in meters. RAW flight line swaths were processed to create 2,390 classified LAS 1.4 files delineated in 1,000 m x 1,000 m tiles. Please note that tiles GB_03743 and GB_05552 do not include valid point return data as they are entirely over areas of open water and thus have not been included in this submission. Each LAS file contains Lidar point information, which has been calibrated, controlled, and classified. Additional derived products include hydro-flattened DEMs, Highest Hit DSMs, Intensity Images, DZ Orthos, Flightline Shapes, Swath Coverage Shapes, Ground Survey Shapes and 3D breaklines of rivers and lakes within the study area.
Ground Conditions: Lidar was collected in summer 2019, while the presence of snow on the ground was at a minimum and rivers were at or below normal levels. In order to post process the Lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, DOWL on behalf of QSI established a total of 194 ground control points distributed throughout the Glacier Bay Delivery 1 project area. Lidar data was calibrated to these known ground locations. An additional 115 independent accuracy checkpoints, 33 in Bare Earth and Urban landcovers (NVA points) and 82 in Shrub, Tall Grass, and Forest categories (VVA points) were used to assess the vertical accuracy of the project data. These checkpoints were not used to calibrate or post process the data.
Note: currently only Delivery 1 of 2 has been released (Blocks 2 & 3, collected in 2019). When the second and final delivery is made available NOAA OCM will incorporate the data and update this metadata record.
This data set is an LAZ (compressed LAS) format file containing LIDAR point cloud data.