Data Management Plan (Deprecated)

Product: 1-meter bare-earth raster digital elevation model (DEM) data tiles in GeoTIFF format.

Geographic Extent: Approximately 4,028 square miles encompassing the Big Island of Hawaii.

Dataset Description: The HI Hawaii Island Lidar NOAA 2017 B17 lidar project called for the planning, acquisition, processing, and production of derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification 2020 Revision A. The data was developed based on a horizontal datum/projection of NAD83 (PA11) UTM Zone 5N Meters (EPSG 6635) and a vertical datum of NAVD88 (GEOID1B) Meters. DEM data was delivered as Geo files formatted to 8,629 individual 1,000-meter x 1,000-meter tiles.

Ground Conditions: Lidar was collected from January 30, 2018 through January 6, 2020 by Leica Geosystems, Inc. while no snow was on the ground 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, Woolpert established 70 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 0 independent accuracy checkpoints (0 NVA points and 0 VVA points), were collected and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

Areas near cliffs with dense vegetation may have poor interpolations over voids. Please see the data use constraints section.

Process Steps:

• 2020-12-29 00:00:00 - Hydro-Flattened Digital Elevation Models (DEMs): Class 2 (ground) lidar points in conjunction with the hydro breaklines as well bridge breaklines were used to create a 1-meter hydro-flattened bare-earth raster DEM. Using automated scripting routines within ArcMap, a GeoTIFF file was created for each tile. Each surface is reviewed using Global Mapper to check for any surface anomalies or incorrect elevations found within the surface. The single photon lidar data acquisition for this award occurred across two separate deployments. The approximate date range of the first acquisition window was from January 2018 to March 2018 and second window was from November 2019 to January 2020. Given the complexity of the terrain, the flight plan for the project included significant overlapping and off-angle lines between the 2018 and 2019/2020 collection which can create more opportunity to notice differences than is normally seen in a lidar collection where lines tend to follow a single direction and acquisition across years is cut into more complete blocks. For each acquisition season, the acquired data was processed and geometrically calibrated by Woolpert’s teaming and data acquisition partner Hexagon. During the calibration, the data was processed to meet the required accuracy specifications per each mission as well as between adjacent missions of the differing flight dates within a given acquisition season. Once the calibration was complete and the data entered full processing, Woolpert made the best efforts to populate delivery tiles containing flights from different acquisition seasons with data acquired from a single season. In these tiles preference was given to the points acquired during the 2018 season because of the significant data processing had occurred within these tiles prior to the second acquisition season. In some areas pieces of lines from the different acquisitions created the edge artifacts. Low confidence polygons were generated around these areas to make the user aware of the discrepancy.
• 2022-10-18 00:00:00 - Data were reorganized into cloud optimized geotiff format and ingested into the Data Access Viewer system.
• 2023-04-14 00:00:00 - Two tiles (5QKB800850.tif and 5QKB810850.tif) were regenerated after their underlying point clouds were re-examined to find ground points near the cliffs. The TIN process was cutting off the cliffs because there were no ground points near the edge and the area was interpolated between the bottom of the cliff and points 50 to 100 meters back from the cliff. This work was done by Woolpert.

Data is available online for bulk or custom downloads