gov.noaa.nmfs.inport:74870 eng UTF8 dataset Elevation National Geodetic Survey resourceProvider NOAA Office for Coastal Management (843) 740-1202 2234 South Hobson Ave Charleston SC 29405-2413 coastal.info@noaa.gov https://coast.noaa.gov WWW:LINK-1.0-http--link NOAA Office for Coastal Management Website NOAA Office for Coastal Management Home Page information pointOfContact 2026-03-04T19:17:17 ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data ISO 19115-2:2009(E) EPSG::6347 2023 NOAA NGS Lidar DEM: Long Island Sound, NY 2025 creation publication NOAA/NMFS/EDM 74870 https://www.fisheries.noaa.gov/inport/item/74870 WWW:LINK-1.0-http--link Full Metadata Record View the complete metadata record on InPort for more information about this dataset. information National Geodetic Survey 1315 East-West Hwy Silver Spring MD 20910 https://geodesy.noaa.gov/ WWW:LINK-1.0-http--link National Geodetic Survey Website Website listed for National Geodetic Survey information originator https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/10273/supplemental/NOAA_NY_Long_Island_Topobathymetric_Lidar_Imagery_Report_Final.pdf WWW:LINK-1.0-http--link Topobathy Lidar Data Report Topobathy Lidar Data Report download 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. This lidar data was required by National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS), Remote Sensing Division Coastal Mapping Program (CMP) to enable accurate and consistent measurement of the national shoreline. The CMP works to provide a regularly updated and consistent national shoreline to define America's marine territorial limits and manage coastal resources. We request that you credit the National Oceanic and Atmospheric Administration (NOAA) when you use these data in a report, publication, or presentation. completed NOAA Office for Coastal Management (843) 740-1202 2234 South Hobson Ave Charleston SC 29405-2413 coastal.info@noaa.gov https://coast.noaa.gov WWW:LINK-1.0-http--link NOAA Office for Coastal Management Website NOAA Office for Coastal Management Home Page information custodian notPlanned https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/10273/supplemental/extent_ngs_longIslandSound_topobathy_m10273.kmz This graphic shows the lidar footprint for this dataset. kmz EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > TOPOGRAPHICAL RELIEF MAPS EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > BATHYMETRY > COASTAL BATHYMETRY EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION theme Global Change Master Directory (GCMD) Science Keywords 17.0 CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > CONNECTICUT CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > NEW YORK place Global Change Master Directory (GCMD) Location Keywords 20.8 LIDAR > Light Detection and Ranging instrument Global Change Master Directory (GCMD) Instrument Keywords 17.2 Airplane > Airplane platform Global Change Master Directory (GCMD) Platform Keywords 17.2 DOC/NOAA/NOS/NGS > National Geodetic Survey, National Ocean Service, NOAA, U.S. Department of Commerce dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2017-04-24 publication 8.5 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 22. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian NGS Lidar project InPort otherRestrictions Cite As: National Geodetic Survey, [Date of Access]: 2023 NOAA NGS Lidar DEM: Long Island Sound, NY [Data Date Range], https://www.fisheries.noaa.gov/inport/item/74870. NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose. otherRestrictions Access Constraints: None otherRestrictions Use Constraints: 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. otherRestrictions Distribution Liability: Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the National Geodetic Survey, the Office for Coastal Management, or its partners. unclassified NOAA Data Management Plan (DMP) NOAA/NMFS/EDM 74870 https://www.fisheries.noaa.gov/inportserve/waf/noaa/nos/ngs/dmp/pdf/74870.pdf WWW:LINK-1.0-http--link NOAA Data Management Plan (DMP) NOAA Data Management Plan for this record on InPort. information crossReference vector eng; US elevation OS Independent Block01 -72.98 -71.79 41.12 41.56 Block01 | Currentness: Ground Condition 2023-03-05 2023-04-11 Block02 -73.93 -72.9 40.73 41.32 Block02 | Currentness: Ground Condition 2023-03-05 2023-07-22 Block03 -73.63 -72.8 40.82 41.01 Block03 | Currentness: Ground Condition 2023-03-16 2023-10-28 Block04 -72.8 -71.76 40.85 41.23 Block04 | Currentness: Ground Condition 2023-04-10 2023-05-30 The NOAA Long Island Sound Topobathymetric Lidar block datasets include all lidar returns. An automated grounding classification algorithm was used to determine bare earth and submerged topography point classification. The automated grounding was followed with manual editing. Classes 2 (ground), 40 (submerged topography), and 43 (submerged object) were used to create the final DEMs. The full workflow used for this project is documented in the NOAA Long Island Sound Topobathymetric Lidar final report. ZIP Zip GeoTIFF NOAA Office for Coastal Management (843) 740-1202 2234 South Hobson Ave Charleston SC 29405-2413 coastal.info@noaa.gov https://coast.noaa.gov WWW:LINK-1.0-http--link NOAA Office for Coastal Management Website NOAA Office for Coastal Management Home Page information distributor https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=10274 WWW:LINK-1.0-http--link Customized Download Create custom data files by choosing data area, product type, map projection, file format, datum, etc. download https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/dem/NGS_LongIslandSound_NY_Topobathy_2023_10274/index.html WWW:LINK-1.0-http--link Bulk Download Simple download of data files. download dataset Horizontal Positional Accuracy Lidar horizontal accuracy is a function of Global Navigation Satellite System (GNSS) derived positional error, flying altitude, and INS derived attitude error. The obtained RMSEr value is multiplied by a conversion factor of 1.7308 to yield the horizontal component of the National Standards for Spatial Data Accuracy (NSSDA) reporting standard where a theoretical point will fall within the obtained radius 95 percent of the time (ACCr). The project specification requires horizontal positions to be accurate to 1.0m(RMSE). Block01, Block02 and Block03: Based on a flying altitude of 400 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.008 meters, the RMSEr value for the Leica Chiroptera shallow green and NIR sensor data is 0.038 meters, with a ACCr of 0.07 meters at the 95% confidence level. The RMSEr value for the Leica Hawkeye deep green sensor data is 0.038 meters, with a ACCr of 0.07 meters at the 95% confidence level based on a flying altitude of 400 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.008 meters. Block04: Based on a flying altitude of 400 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.008 meters, the RMSEr value for the Leica Chiroptera shallow green and NIR sensor data for Block04 is 0.038 meters, with a ACCr of 0.07 meters at the 95% confidence level. The RMSEr value for the Leica Hawkeye deep green sensor data in Block04 is 0.051 meters, with a ACCr of 0.09 meters at the 95% confidence level based on a flying altitude of 400 meters, an IMU error of 0.004 decimal degrees, and a GNSS positional error of 0.008 meters. Please refer to the NOAA Long Island Sound Topobathymetric Lidar final data report for final accuracies. Vertical Positional Accuracy Absolute accuracy was assessed using both Non-Vegetated Vertical Accuracy (NVA) and Vegetated Vertical Accuracy (VVA) survey methods. Survey checkpoints were evenly distributed as feasible throughout the project area. NVA compares known ground check point data that were withheld from the calibration and post-processing of the lidar point cloud to the derived gridded bare earth DEM. NVA is a measure of the accuracy of lidar point data in open areas with level slope (less than 20°) where the lidar system has a high probability of measuring the ground surface and is evaluated at the 95% confidence interval (1.96*RMSE). Project specifications require NVA meet 0.196 m accuracy at the 95% confidence interval. Ground check points located in land cover categories other than bare earth or urban were used to compute the Vegetated Vertical Accuracy (VVA). Project specifications require VVA meet 0.294 m based on the 95th percentile tested against the derived bare earth DEM. Please refer to the NOAA Long Island Sound Topobathymetric Lidar final data report for final accuracies. Block01: The Block01 dataset Non-Vegetated Vertical Accuracy tested 0.058 m vertical accuracy at 95% confidence level against the derived bare earth DEM in open terrain using 13 ground check points, based on RMSEz (0.030 m) x 1.9600. The Vegetated Vertical Accuracy tested 0.108 m vertical accuracy at the 95th percentile against the derived bare earth DEM using 11 landclass points. Block02: The Block02 area dataset Non-Vegetated Vertical Accuracy tested 0.057 m vertical accuracy at 95% confidence level against the derived bare earth DEM in open terrain using 16 ground check points, based on RMSEz (0.029 m) x 1.9600. The Vegetated Vertical Accuracy tested 0.111 m vertical accuracy at the 95th percentile against the derived bare earth DEM using 10 landclass points. Block03: The Block03 area dataset Non-Vegetated Vertical Accuracy tested 0.049 m vertical accuracy at 95% confidence level against the derived bare earth DEM in open terrain using 5 ground check points, based on RMSEz (0.025 m) x 1.9600. The Vegetated Vertical Accuracy tested 0.158 m vertical accuracy at the 95th percentile against the derived bare earth DEM using 5 landclass points. Block04: The Block04 area dataset Non-Vegetated Vertical Accuracy tested 0.060 m vertical accuracy at 95% confidence level against the derived bare earth DEM in open terrain using 10 ground check points, based on RMSEz (0.031 m) x 1.9600. The Vegetated Vertical Accuracy tested 0.461 m vertical accuracy at the 95th percentile against the derived bare earth DEM using 6 landclass points. 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. 2024-11-15T00:00:00 National Geodetic Survey processor 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. 2024-11-15T00:00:00 National Geodetic Survey processor 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. 2024-11-15T00:00:00 National Geodetic Survey processor 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. 2024-11-15T00:00:00 National Geodetic Survey processor 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. 2024-11-15T00:00:00 National Geodetic Survey processor Acquisition and Processing NV5 originator