2019 - 2020 NOAA NGS Topobathy Lidar DEM: Hurricane Michael (NW Florida)

The NOAA Michael Topobathymetric Lidar Delivery 1 extent covers 95,557 acres of the full project boundary. This Delivery 1 dataset is comprised of 2,286 - 500 m x 500 m LAS tiles.

The NOAA Michael Topobathymetric Lidar Delivery 3 UTM 16 extent covers 341,153 acres of the full project boundary.

The NOAA Michael Topobathymetric Lidar Delivery 3 UTM 17 extent covers 341,153 acres of the full project boundary.

The NOAA Michael Topobathymetric Lidar Delivery 41 (Block 04) extent covers 192,811 acres of the full project boundary.

The NOAA Michael Topobathymetric Lidar Delivery 2 extent covers 166,578 acres of the full project boundary. This Delivery 2 dataset is comprised of 3,549 - 500 m x 500 m LAS tiles.

The NOAA Michael Topobathymetric Lidar Delivery 42 (Block 05) extent covers 95,557 acres of the full project boundary. This Block 05 dataset is comprised of 9,006 - 500 m x 500 m LAS tiles.

The NOAA Michael Topobathymetric Lidar Delivery 43 (Block 06) extent covers 153,351 acres of the full project boundary. This Block 06 dataset is comprised of 3,539 - 500 m x 500 m LAS tiles.

The NOAA Michael Topobathymetric Lidar Delivery 44AA (Block 07)extent covers 276,009 acres of the full project boundary. This Block 07 dataset is comprised of 5,706 - 500 m x 500 m LAS tiles.

The NOAA Michael Topobathymetric Lidar Delivery 44B (Block 08) extent covers 327,801 acres of the full project boundary. This Delivery 44B dataset is comprised of 5,826 - 500 m x 500 m LAS tiles.

Delivery 44B (Block 08) acquisition dates spanned from 20191126-20200428 in 24 missions.

Delivery 41 (Blcok 04) acquisition dates spanned from 20201127-20200409 in twenty-one missions.

Block 1 collection dates.

Delivery 3 UTM 16 acquisition dates spanned from 20201127-20200730 in forty-seven missions.

Delivery 43 (Block 06) acquisition dates spanned from 20191204-20200502 in twenty one missions.

Delivery 42 (Block 05) acquisition dates spanned from 20191215-20200627 in thirty-three missions.

Delivery 2 acquisition dates spanned from 20200101-20200730 in twenty one missions.

Delivery 44AA (Block 07) acquisition dates spanned from 20200127-20200428 in twenty-two missions.

Delivery 3 UTM 17 acquisition dates spanned from 20200215-20200519 in fifteen missions.

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base.

Simple download of data files.

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

Data for the NOAA Michael Topobathymetric Lidar project area was acquired by Quantum Spatial (QSI) using a Leica Chiroptera 4X Topobathy lidar system. All derived LAS data was referenced to:

Horizontal Datum-NAD83(2011) epoch: 2010.00

Projection-UTM Zone 16N and UTM17N

Horizontal Units-meters

Vertical Datum-GRS80 Ellipsoid

Vertical Units-meters

The collected Lidar data were immediately processed in the field by QSI 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 in POSPAC MMS 8.3 SP3 and loaded into RiProcess which applies pre-calibrated angular misalignment corrections of scanner position to extract the raw point cloud into geo-referenced LAS files. These files were inspected for sensor malfunctions and then passed through automated raster generation using LAStools to develop an initial assessment of bathymetric coverage. QSI reviewed all acquired flight lines to ensure complete coverage and positional accuracy of the laser points. These rasters were also used to create an initial product in 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.

QSI resolved kinematic corrections for aircraft position data using aircraft GNSS and Applanix's proprietary PP-RTX solution. When PP-RTX was not used QSI 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 final SBET creation, QSI 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. All LiDAR data below water surface models were classified as water column to correct for refraction. 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. Using raster-based QC methods, the output data is verified to ensure the refraction tool functioned properly.

Dewberry performed the calibration of the NOAA Michael Delivery 1 Lidar dataset in addition to the point cloud classification in order to create the final topobathymetric lidar deliverables which were subsequently reviewed by QSI.

Relative accuracy of the green swaths compared to overlapping and adjacent green swaths as well as the relative accuracy of green swaths compared to overlapping and adjacent NIR swaths was verified through the use of Delta-Z (DZ) orthos. Dewberry created DZ rasters using proprietary processing tools. The intraswath or within a swath accuracy were verified using GIS software. Profiles of elevated planar features, such as roofs, were used to verify horizontal alignment between overlapping swaths.

All lidar data was peer-reviewed. QAQC also included creating void polygons for use during review. All necessary edits were applied to the dataset. NV5 Geospatial's proprietary software, LAS Monkey, was used to update LAS header information, including all projection and coordinate reference system information. The final lidar data is in LAS format 1.4 and point data record format 6.

The contractor delivered classification scheme is as follows:

1- Unclassified

2- Ground

7- Noise

40- Bathymetric bottom or submerged topography

41- Water surface

43- Submerged object

45- water column

46- 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

85- water column associated with areas of overlap bathy bottom/temporal bathymetric differences

1Overlap- Edge clip

1Withheld- Green laser returns in topo only areas

42Synthetic- derived water surface

All data was then verified by an Independent QC department. The independent QC was performed by separate analysts who did not perform manual classification or editing. The independent QC involved quantitative and qualitative reviews.

Dewberry transformed the final LiDAR data from ellipsoid heights to orthometric heights referenced to NAVD88, Geoid12b to create the final topobathymetric void clipped DEMs. The topobathymetric bare earth DEMs were output at 1 meter resolution in GeoTIFF format into 5000 m x 5000 m tiles. The rasters are 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.

The NOAA Office for Coastal Management (OCM) received tiff files in UTM Zone 17N and 16N NAD83(2011), meters coordinates. Vertical positions were provided in NAVD88 (Geoid18) elevations and in meters. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The data were converted to Cloud Optimized GeoTiff (COG) format and the projection and vertical datum EPSG codes were assigned.

2. The data were copied to https