Data Management Plan (Deprecated)

2023 NOAA NGS Lidar DEM: Long Island Sound, NY

NOAA Long Island Sound Topobathymetric Lidar data were collected by NV5 using Leica Chiroptera/Hawkeye 4X and Chiroptera/Hawkeye 5 systems in four blocks. Block01 was flown between 20230305 and 20230411 in 14 missions, block02 was flown between 20230305 and 20230722 in 23 missions, block03 was flown between 20230316 and 20231028 in 13 missions and block04 was flown between 20230410 and 20230530 in 19 missions.

The final classified lidar data were then transformed from ellipsoid (GRS80) to orthometric height (Geoid18) and used to create topobathymetric DEMs in Cloud Optimized GeoTIFF format with 1m pixel resolution.

One-time data collection

2023-03-05 to 2023-04-11, 2023-03-05 to 2023-07-22, 2023-03-16 to 2023-10-28, 2023-04-10 to 2023-05-30

W: -72.98, E: -71.79, N: 41.56, S: 41.12

Block01

W: -73.93, E: -72.9, N: 41.32, S: 40.73

Block02

W: -73.63, E: -72.8, N: 41.01, S: 40.82

Block03

W: -72.8, E: -71.76, N: 41.23, S: 40.85

Block04

Model (digital)

No information found

NOAA Office for Coastal Management (NOAA/OCM)

Metadata Contact

NOAA Office for Coastal Management (NOAA/OCM)

coastal.info@noaa.gov

(843) 740-1202

No information found

Data Steward

Yes

Unknown

Process Steps:

• 2024-11-15 00:00:00 - Data for the NOAA Long Island Sound Topobathymetric Lidar block areas were acquired by NV5 using Leica Chiroptera/Hawkeye 4X and Chiroptera/Hawkeye 5 topobathymetric lidar systems. All derived DEM data is referenced to: Horizontal Datum-NAD83(2011) epoch: 2010.00 Projection-UTM Zone 18N Horizontal Units-meters Vertical Datum-NAVD88 (Geoid18) Vertical Units-meters NOAA provided NV5 with a project boundary for the NOAA Long Island Sound project. Using a 50 meter buffered boundary, NV5 created an airborne lidar acquisition plan. The collected lidar data were immediately processed in the field by NV5 to a level that will allow QA\QC measures to determine if the sensor is functioning properly and assess the coverage of submerged topography. An initial SBET was created using Waypoint Inertial Explorer 8.90, and the raw data were extracted into geo-referenced LAS files using Lidar Survey Studio 3.0 with pre-calculated scanner misalignment angles determined through a boresight protocol. These files were inspected for errors and then passed through an automated workflow, producing rasters to develop an initial assessment of bathymetric coverage. NV5 reviewed all acquired flight lines to ensure complete coverage and positional accuracy of the laser points. These rasters were also used to create Quick Look Coverage Maps. These Quick Look files are not fully processed data or final products but provide rapid assessment of approximate coverage and depth penetration.
• 2024-11-15 00:00:00 - NV5 resolved kinematic corrections for aircraft position data using aircraft GNSS and Applanix's proprietary PP-RTX solution. When PP-RTX was not used NV5 conducted static Global Navigation Satellite System (GNSS) ground surveys (1 Hz recording frequency) using base stations over known monument locations during flights. After the airborne survey, static GPS data were triangulated with nearby Continuously Operating Reference Stations (CORS) using the Online Positioning User Service (OPUS) for precise positioning. Multiple independent sessions over the same base station were performed to confirm antenna height measurements and to refine position accuracy. This data was used to correct the continuous on board measurements of the aircraft position recorded throughout the flight. A final smoothed best estimate trajectory (SBET) was developed that blends post-processed aircraft position with attitude data. Using the SBETs, sensor head position and attitude were then calculated throughout the survey. Trimble Business Center v.3.90, Blue Marble Geographic Calculator 2019, and PosPac MMS 8.3 SP3 were used for these processes. Following the final SBET creation, NV5 used Leica Lidar Survey Studio (LSS) to calculate laser point positioning by associating SBET positions to each laser point return time, scan angle, and intensity. Leica LSS was used to derive a synthetic water surface to create a water surface model. Light travels at different speeds in air versus water and its direction of travel or angle is changed or refracted when entering the water column. The refraction tool corrects for this difference by adjusting the depth (distance traveled) and horizontal positioning (change of angle/direction) of the lidar data. All lidar data below water surface models were classified as water column to correct for refraction. Using raster-based QC methods, the output data is verified to ensure the refraction tool functioned properly.
• 2024-11-15 00:00:00 - Once all data was refracted by flight line, the data was exported to LAS 1.4 format and combined into 500 m x 500 m tiles. Data were then further calibrated using TerraMatch. NV5 used custom algorithms in TerraScan to classify the initial ground/submerged topography surface points. Relative accuracy of overlapping swaths was compared and verified through the use Delta-Z (DZ) orthos created using NV5's Las Product Creator. Absolute vertical accuracy of the calibrated data was assessed using ground survey data and complete coverage was again verified.
• 2024-11-15 00:00:00 - Post automated classification NV5 then performed manual editing to review all classification and improve the final topobathymetric surface. NV5's LasMonkey was used to update LAS header information, including all projection and coordinate reference system information. The final lidar data are in LAS format 1.4 and point data record format 6. The final classification scheme is as follows: 1 - Unclassified 1W - Withheld - edge clip 1OW - Overlap Withheld - unrefracted green data from Chiroptera sensor 2 - Ground 7W - Withheld -low noise 18W - Withheld - high noise 40 - Bathymetric bottom or submerged topography 41 - Water surface 42S - Synthetic- Chiroptera synthetic water surface 43 - Submerged feature 45 - Water column 64 - Submerged Aquatic Vegetation (SAV) 65 - Overlap bathy bottom - temporally different from a separate lift 71 - Unclassified associated with areas of overlap bathy bottom/temporal bathymetric differences 72 - Ground associated with areas of overlap bathy bottom/temporal bathymetric differences 81 - Water surface associated with areas of overlap bathy bottom/temporal bathymetric differences 82S - Synthetic - Chiroptera synthetic water surface associated with areas of overlap bathy bottom/temporal bathymetric differences 85 - Water column associated with areas of overlap bathy bottom/temporal bathymetric differences.
• 2024-11-15 00:00:00 - NV5 transformed the final lidar data from ellipsoid heights to orthometric heights referenced to NAVD88, Geoid 18 to create the final topobathymetric void clipped DEMs. The topobathymetric bare earth DEMs were output at 1 meter resolution in GeoTIFF format. The NOAA Long Island Sound Topobathymetric Lidar raster DEM is clipped to the extent of the project boundary and named according to project specifications. A bathymetric void shapefile was created to indicate areas where there was a lack of bathymetric returns. This shape was created by triangulating bathymetric bottom points with an edge length maximum of 4.56m to identify all areas greater then 9 square meters without bathymetric returns. This shapefile was used to clip and exclude interpolated elevation data from these areas in the bathymetric void clipped topobathymetric bare earth model.

No information found

No

NMFS Office of Science and Technology

https://www.fisheries.noaa.gov/inport/item/74870

Metadata produced and maintained in accordance with the NOAA Data Documentation Procedural Directive: https://nosc.noaa.gov/EDMC/DAARWG/docs/EDMC_PD-Data_Documentation_v1.pdf

Yes

NOAA Office for Coastal Management (NOAA/OCM)

Data is available online for bulk and custom downloads.

No information found

NCEI_CO

Office for Coastal Management - Charleston, SC

No information found

Data is backed up to tape and to cloud storage.