2018-2020 HI Hawaii Island Lidar Hydro-Flattened Bare-Earth DEM

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.

This data is intended for use in coastal management decision making, including applications such as support for local hydrologists and watershed managers in their decision-making processes and for formulating a sediment budget and identifying soil erosion hotspots.

USGS Contract No. G16PC00022, NOAA Contract No. EA133C33CQ0010. USGS Task Order No. G17PD01353. NOAA Task Order No. T-0040. CONTRACTOR: Woolpert. Sub-contractor: Leica Geosystems, Inc.

Raster File Type = TIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 1 Meter

Interpolation or Resampling Technique = Triangulated Irregular Network

Required Vertical Accuracy = 19.6 cm NVA

This work was funded by: NOAA Office for Coastal Management, FEMA Region 9, FEMA HQ, USDA NRCS, County of Hawaii, USGS HVO, and USGS 3DEP

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners

Data is available online for bulk or custom downloads

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

The point cloud used to derive this dataset is known to have areas where the dense vegetation prevented reliable ground classification of the points. In such areas near cliffs, interpolation over the void areas for this DEM may have resulted in a very poor representation of the cliff area. Attempts have been made to remediate that issue in at least one area, but there are likely to be more areas. Care should be taken to examine the voids in the original point cloud when analyzing cliff areas in this dataset.

Microsoft Windows 10 Version 1607 (Build 14393.2189); ArcMap 10.7; ArcCatalog 10.7; TerraScan ver. 20; TerraModeler ver. 20; Geocue 2018.2.59.5; GDAL 2.4.0.

NOAA collected independent checkpoints located in non-vegetated and vegetated land cover classes in order to perform independent vertical accuracy testing on the lidar point cloud swath and DEM data. Preliminary quantitative value: 0.11 meters RMSE in non-vegetated areas, 0.50 m in vegetated areas. These figures were calculated by Woolpert using the NOAA checkpoints.

USGS Determined DEM Vertical Accuracy:

Non-Vegetated Vertical Accuracy (NVA) = 20.84 cm at 95% Confidence Level or 10.63 cm RMSE

Vegetated Vertical Accuracy (VVA) =111.37 cm at the 95th Percentile

Datasets contain complete coverage of tiles. A visual qualitative assessment was performed to ensure data completeness. The DEM is of good quality and data passes Non-Vegetated and Vegetated Vertical Accuracy specifications.

Data covers the entire area specified for this project.