This data set is comprised of a hydro-flattened digital elevation model (DEM). The total area collected for Horry County, SC for this project is approximately 1092 square miles. Lidar data was collected and processed to meet the requirements of the project task order. The lidar collection was a collaborative effort between two data acquisition firms. While Woolpert was responsible for collection of the majority of the county, the coastal portion of the data was collected by Quantum Geospatial and is detailed in the processing steps of the metadata. Lidar data is a remotely sensed high resolution elevation data collected by an airborne platform. The lidar sensor uses a combination of laser range finding, GPS positioning, and inertial measurement technologies. The lidar systems collect data point clouds that are used to produce highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures, and vegetation. The task required the LiDAR data to be collected at a nominal pulse spacing (NPS) of 0.7 meters. The final products include classified LAS, four (4) foot pixel raster DEMs of the bare-earth surface in ERDAS IMG Format. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Ground conditions: Water at normal levels; no unusual inundation; no snow. The bare earth DEMs along the coast may have a variance in the water heights due to temporal differences during the lidar data acquisition and will be represented in DEM as a seam-like anomaly. One coastal elevation was applied to entire project area. Due to differing acquisition dates and thus differing tide levels there will be areas in the DEM exhibiting what appears to be "digging" water features. Sometimes as much as approximately 2.5 feet. This was done to ensure that no coastal hydro feature was "floating" above ground surface. This coastal elevation will also affect connected river features wherein a sudden increase in flow will be observed in the DEM to accommodate the coastal elevation value. During Hydrologic breakline collection, Woolpert excluded obvious above-water piers or pier-like structures from the breakline placement. Some features extend beyond the apparent coastline and are constructed in a manner that can be considered an extension of the ground. These features were treated as ground during classification and subsequent hydrologic delineation. In all cases, professional practice was applied to delineate what appeared to be the coast based on data from multiple sources; Due to the many substructures and the complexity of the urban environment, interpolation and apparent "divots" (caused by tinning) may be evident in the surface of the bare earth DEM. In all cases, professional practice was applied to best represent the topography. The data received by the NOAA OCM are topographic data in LAS 1.2 format, classified as unclassified (1), ground (2), all noise (7), water (9), ignored ground (10), overlap unclassified (17), and overlap ground (18). Digital Elevation Models (DEMs) and breakline data are also available. Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office of Coastal Management (OCM) or its partners. Original contact information: Contact Org: Woolpert Phone: (937) 461-5660

Original Product: Hydroflattened Digital Elevation Model (DEM) data covering the NOAA AK Communities 2025 project area. Original Geographic Extent: This dataset and derived products encompass an area covering approximately 286,327 acres of Southwest Alaska. Original Dataset Description: Lidar flight line swaths were processed to create 2,299 classified LAZ 1.4 files delineated in 750m x 750m tiles. Each LAZ file contains lidar point information, which has been calibrated, controlled, and classified. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create 2,299 - 0.5 meter hydro-flattened Raster DEMs delineated in 750m x 750m tiles. Non-Vegetated Vertical Accuracy (NVA) was assessed using 43 check points located on bare earth in clear, unobstructed areas. Vegetated Vertical Accuracy (VVA) was assessed using 19 check points in Tall Grass, Forest, and Shrub landcover types. Additional products include classified LAZ files, intensity images, maximum surface height rasters, and 3D breaklines of water bodies within the study area. Ground Condition: Ground conditions contained snow at high elevations and acquisition occurred free of smoke, fog and cloud cover

The Digital Elevation Model includes the grounded classes of class 2, 40, and 43. This raster is tiled out into 23 5000 m x 5000 m tiles. The project AOI covers approximately 161.5 square kilometers, and includes the area from Whitefish Point to Bay Mills, MI in Eastern Lake Superior, the eastern portion of which falls within and EPA's St. Marys River area of concern.

Original Product: Hydroflattened Digital Elevation Model (DEM) data covering the NOAA AK Communities 2025 project area. Original Dataset Geographic Extent: This dataset and derived products encompass five areas covering approximately 92,475 acres of Southwest Alaska. Original Dataset Description: Lidar flight line swaths were processed to create 825 classified LAS 1.4 files delineated in 750m x 750m tiles tiles. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create 825 - 0.5 meter hydro-flattened Raster DEMs delineated in 750m x 750m tiles tiles. Non-Vegetated Vertical Accuracy (NVA) was assessed using 101 check points located on bare earth in clear, unobstructed areas. Vegetated Vertical Accuracy (VVA) was assessed using 26 check points in Tall Grass, Forest, and Shrub landcover types. Additional products include classified LAS files, intensity images, maximum surface height rasters, and 3D breaklines of water bodies within the study area. Ground Condition: Ground conditions were free of snow and acquisition occurred free of smoke, fog and cloud cover.

NOAA Florence Topobathymetric Lidar data were collected by NV5 Geospatial (NV5) in 9 blocks from 20191126 - 20200825 using the follow sensors: Block01 -Riegl VQ880GII system Block02 - Riegl VQ-880-G and Riegl VQ-880-GII systems Block03 - Riegl VQ880G, Riegl VQ880GII, and Riegl VQ880GH systems Block04 - Riegl VQ880GII and Leica Chiroptera 4x systems Block05 - Riegl VQ880GII, Leica Chiroptera 4x and Hawkeye systems Block06 - Riegl VQ880GII, Leica Chiroptera 4x and Hawkeye systems Block07 - Riegl VQ880G, Riegl VQ880GII, and Leica Chiroptera 4x systems Block08 - Riegl VQ880G and Riegl VQ880GII systems Block09 - Riegl VQ880G and Riegl VQ880GII systems This dataset includes topobathymetric data in a LAS format 1.4, point data record format 6, with classifications in accordance with project specifications and the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards. This data set also includes LiDAR intensity values, number of returns, return number, time, and scan angle. The 100 meter buffered project area consists of approximately 3,075,010 acres along the Eastern coast of Virginia, North Carolina, and South Carolina. The delivered classified lidar data were then transformed from ellipsoid to geoidal height (Geoid18) and used to create topobathymetric DEMs in GeoTIFF format with 1m pixel resolution.

This dataset is a digital elevation model (DEM) derived from LiDAR (Light Detection and Ranging) point cloud data of the coastal tidal parts of Skagit and Snohomish Counties in WA State. The National Oceanic and Atmospheric Administration’s Office for Coastal Management contracted with Tetra Tech to acquire and process airborne LiDAR over an area of about 186 square miles. Data was to be acquired within a 2 hour window of low tide. Deliverables included classified LiDAR point clouds, breaklines and digital elevation models (DEM). LiDAR data was acquired on 13 and 14 of August 2019. The coastal area was covered in one flight on 8/14 while the inland area was covered on 8/13. The coastal flight took place on 8/14 with a tide window between -0.7 and +0.5 foot. For the airborne LiDAR flight Tetra Tech subcontracted with Eagle Mapping. The data was acquired with a Riegl LMS VQ780i sensor. A ground control survey was conducted to collect calibration points and check points. For the aerial acquisition Tetra Tech contracted with Eagle Mapping. For the ground survey, Tetra Tech contracted with Compass Data. The LiDAR data and derivative products were to be based on the USGS LiDAR Base Specifications. The coordinate reference system is UTM Zone 10N meters, NAD83(2011). The vertical datum is NAVD88 with Geoid12B.

These data were collected by Dewberry using a CZMIL Super Nova system. The data were acquired from 20220719 through 20220816. The data are rasterized topobathy lidar elevations at a 1 m grid spacing. This dataset consists of approximately 219 square miles of data along the shores of Green Bay and contains 2,630 500 m x 500 m GeoTiff files. In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from are also available from the NOAA Digital Coast. A link to these data are provided in the URL section of this metadata record.

Original Dataset Product: 0.5-meter bare-earth raster digital elevation model (DEM) data tiles in GeoTIFF format. Original Dataset Geographic Extent: HI_NOAAMauiOahu_3: The work unit covers approximately Approximately 306 square miles on the eastern side of the big island of Hawaii. Original Dataset Description: HI_NOAAMauiOahu_3 (Big Island) The HI_NOAAMauiOahu_3_B20 lidar project called for the planning, acquisition, processing, and production of derivative products of QL1 lidar data to be collected an aggregate nominal pulse spacing (ANPS) of 0.35-meters and 8 points per square meter (ppsm). Project specifications were based on the National Geospatial Program Lidar Base Specification Version 2.1, and the American Society of Photogrammetry and Remote Sensing (ASPRS) Positional Accuracy Standards for Digital Geospatial Data (Edition 1, Version 1.0). The data was developed based on a horizontal reference system of NAD83 (PA11), UTM 5 (EPSG 6635), Meter, and a vertical reference system of NAVD88 (GEOID12B), Meter. DEM data was delivered as processed GeoTIFF files formatted to 3,450 individual 500-meters x 500-meters tiles. Note: Between 2020 and 2023 multiple mobilizations were made to collect the data in the project area due to the extreme terrain and persistent low clouds. On March 31, 2023, it was decided between Woolpert and USGS to end the acquisition phase of the project and move onto processing with the data collected. The DPA and work unit has been clipped to the extent of the data collected. Areas of low point density and/or small data voids within the work unit have been identified with low confidence polygons. Original Dataset Ground Conditions: HI_NOAAMauiOahu_3 (Big Island) Lidar was collected from February 14, 2023, through March 15, 2023 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 ground control points that were used to calibrate the lidar to known ground locations established throughout the entire project area. An additional independent accuracy checkpoints were collected throughout the entire project area and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

Product: Processed, classified lidar point cloud data tiles in LAS 1.4 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 (GEOID12B) Meters. Lidar data was delivered as processed LAS 1.4 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. Additional independent accuracy checkpoints were collected by NOAA and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. This dataset has been noted to have issues with ground classification in areas of dense vegetation. Please read the data use constraints section for further details.

The NOAA Maine Topbathymetric Lidar was collected by NV5 using Leica Chiroptera Hawkeye 4X systems. The lidar acquisitions were flown between 20221006 and 20231216 in 120 missions. The final classified lidar data were then transformed from ellipsoid (GRS80) to geoidal height (Geoid18) and used to create topobathymetric DEMs in Cloud Optimized GeoTIFF format with 1m pixel resolution.