Woolpert, Inc. was contracted to acquire and process topographic-bathymetric lidar for the islands of Anatahan, Alamagan, Guguan, and Sarigan in response to Hurricane Yutu for Quantum Spatial, Inc. (QSI). Woolpert collected lidar using their Leica HawkEye 4X (HE4X) topo-bathy lidar sensor that consists of a Chiroptera 4X (CH4X) sensor, with an additional Leica 40kHz deep bathymetric channel to provide high density topo lidar. The HE4X is a latest generation topographic and bathymetric lidar sensor. The system provides denser data than previous traditional bathymetric lidar systems. It is unique in its ability to acquire bathymetric lidar, topographic lidar and 4-band digital camera imagery simultaneously. The HE4X provided 300 kHz topographic data, an effective 140 kHz shallow bathymetric data and 40 kHz deep bathymetric data. 4-band 80 MP digital camera imagery was also collected simultaneously with the sensor’s RCD-30 camera. The bathymetric and topographic lasers are independent and do not share an optical chain or receivers, so they are optimized for their specific function. As with any bathymetric lidar, maximum depth penetration is a function of water clarity and seabed reflectivity. The HE4X is designed to penetrate to 3 times the secchi depth. This is also represented as Dmax = 4/K, where K is the diffuse attenuation coefficient, and assuming K is between 0.1 and 0.3, a normal sea state and 15% seabed reflectance. Both the topographic and bathymetric sub-systems use a palmer scanner to produce an elliptical scan pattern of laser points with a degree of incidence ranging from +/-14 degrees (front and back) to +/-20 degrees (sides), providing a 40 degrees field of view. This has the benefit of providing multiple look angles on a single pass and helps to eliminate shadowing effects. This can be of particular use in urban areas, where all sides of a building are illuminated, or for bathymetric features such as the sides of narrow water channels or features on the seafloor such as smaller objects and wrecks. It also assists with penetration in the surf zone where the back scan passes the same ground location a couple of seconds after the front scan, allowing the areas of whitewater to shift. All topo lidar data for this project were collected simultaneous to meet United States Geological Survey, Quality Level 1 (USGS QL1) with a minimum of 8 pts per square meter at an accuracy of 10cm RMSEz. A minimum of 2 points per square meter were acquired for bathymetric lidar data. For practical purposes the survey area was divided into survey blocks in each island, allowing acquisition to be conducted in the most efficient and consistent manner possible. The data includes topobathy data in an LAS 1.4 format file along with associated bare earth digital elevation models (DEM). The dataset was derived from topobathymetric data in a LAS format 1.4, point data record format 6, with the following classifications in accordance with project specifications and the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards: 1 - unclassified 2 - ground 7 - noise 40 - bathymetric bottom or submerged topography 41 - water surface 42 - derived water surface 43 - manmade submerged feature 45 - water column 1 Overlap - edge clip 1 Withheld - bathy land User data values differentiates between NIR and green lasers. A value of of 1 indicates the point is from the NIR laser, and a values of 2-5 indicate the green laser. This dataset is the ellipsoid point cloud data set.

These data were collected by the National Oceanic Atmospheric Administration National Geodetic Survey Remote Sensing Division using a Leica Chiroptera 4X system. The data were acquired from 20210729 - 20220814. The data includes topobathy data in an LAS 1.4 format file classified as unclassified (1), ground (2), noise (7), water surface (topographic sensor) (9), high noise (18), bathymetric point (40), water surface (41), synthetic water surface (42), submerged feature (43) in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards. This data set may also include lidar intensity values.

These data were collected by Woolpert using a Leica Hawkeye4X system. The data were acquired from from November 3, 2022 through February 5, 2023. The data includes topobathy data in an LAS 1.4 format file classified as unclassified (1), ground (2), low noise (7), topo water surface (9), high noise (18), bathymetric point (40), bathymetric water surface (41), synthetic derived water surface (42), and submerged object (43), in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards.

These data were collected by Woolpert using a Leica Hawkeye4X system. Data for Niihau were acquired from September 8, 2021 through September 26, 2021. The data includes topobathy data in an LAS 1.4 format file classified as unclassified (1), ground (2), low noise (7), topo water surface (9), high noise (18), bathymetric point (40), bathymetric water surface (41), synthetic derived water surface (42), submerged object (43), International Hydrographic Organization (IHO) S-57 object (44), submerged aquatic vegetation (64), and bathymetric bottom temporal changes (65) in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards. This data set may also include lidar intensity values and encoded RGB image values.

These data were collected by Dewberry using a CZMIL Super Nova system. The data were acquired from 20220719 through 20220816. The data include topobathy data in LAS 1.4 format classified as unclassified (1); ground (2); low noise (7); high noise (18); bathymetric bottom (40); water surface (41); derived water surface (42); submerged object, not otherwise specified (e.g., wreck, rock, submerged piling) (43); and no bottom found (bathymetric lidar point for which no detectable bottom return was received) (45). 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 LAS tiles. In addition to the lidar point data, topobathy bare earth Digital Elevation Models (DEMs) at a 1 meter grid spacing, created from the lidar point data are available from the NOAA Digital Coast. A link to this data is provided in the URL section of this metadata record.

This data was collected by Woolpert using a Leica Hawkeye4X system. The data were acquired from from November 3, 2022 through Feburary 5, 2023. The data includes topobathy 1m gridded DEM data generated from classes ground (2), bathymetric point (40) and submerged object (43) in the classified point cloud, in accordance with project specifications. The project consists of approximately 3251 square kilometers of data along the Chesapeake Bay coastline. This dataset contains 5000m x 5000m topobathy 1m DEM tiles.

These data were collected by Woolpert using a Leica Hawkeye4X system. The data were acquired from from November 3, 2022 through March 5, 2023. The data includes topobathy data in an LAS 1.4 format file classified as unclassified (1), ground (2), low noise (7), topo water surface (9), high noise (18), bathymetric point (40), bathymetric water surface (41), synthetic derived water surface (42), and submerged object (43), in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards.

These data were collected by Leading Edge Geomatics using a Riegl VQ-880-G II sensor. The data acqusition began January 20, 2019 through June 2, 2019. The data includes topobathy data in LAS 1.4 format classified as created, never classified (0); unclassified (1); ground (2); noise (7); bathymetric bottom (40); water surface (41); derived water surface (42); submerged object, not otherwise specified (e.g., wreck, rock, submerged piling) (43); International Hydrographic Organization S-57 object, not otherwise specified (44); no bottom found (bathymetric lidar point for which no detectable bottom return was received) (45); bathymetic bottom temporal changes (46) in accordance with project specifications.

This data was collected by NOAA using a Riegl VQ880G sensor. The data was acquired August 5, 2017. The data includes topobathy data in LAS 1.2 format classified as created,unclassified (1); ground (2); topographic noise (7); bathymetric noise (22); water column (25); bathymetric bottom (26); water surface (27); International Hydrographic Organization S-57 object; not otherwise specified (30), in accordance with project specifications. The project consists of approximately 34 square miles of data along the shores of St. Jeromes Creek. This dataset contains 342 500 m x 500 m lidar tiles.

The NOAA Chesapeake Bay MD1804 Option 1 East 4 Topobathymetric lidar data were collected by NV5 Geospatial (NV5) using Riegl VQ-880-G, VQ-880-GII, and VQ-880-GH systems. The NOAA Chesapeake Bay MD1804 Option 1 East 4 acquisition spanned from 20181107-20190417 in 14 missions. The NOAA Chesapeake Bay MD1804 Option 1 East 4 dataset includes topobathymetric data in LAS format 1.4, point data record format 6, with the following classifications in accordance with project specifications and the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards: 1 - unclassified 2 - ground 7 - noise 40 - bathymetric bottom or submerged topography 43 - submerged feature 45 - water column 46 - overlap bathymetric bottom 71 - adjacent lift unclassified 72 - adjacent lift ground 85 - adjacent lift water column 1 Overlap - edge clip This data set also includes lidar intensity values, number of returns, return number, time, and scan angle. The 100 meter buffered NOAA Chesapeake Bay MD1804 Option 1 East 4 project area covers approximately 563.829 square kilometers of an area encompassing a portion of the Chesapeake Bay and the nearby census designated places of Taylors Island, Cambridge, Madison, Woolford, and Algonquin, Maryland. LAS files were compiled in 500 m x 500 m tiles. The final classified lidar data were then transformed from ellipsoid to geoidal height (Geoid12b) and used to create 36 - 5,000 m x 5,000 m topobathymetric DEMs in GeoTIFF format with 1m pixel resolution.