Data Management Plan (Deprecated)

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 132 individual 1250 ft x 1250 ft tiles clipped to the DPA; used to create Bare-Earth DEMs and all-return MSHRs as necessary.

Geographic Extent: Gloucester (Catlett Islands AOI), James City (Taskinas Creek AOI), King William (Sweet Hall Marsh AOI), and York (Goodwin Islands AOI) Counties, Virginia, covering approximately 7.3 square miles.

Dataset Description: The lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Lidar Base Specification 2024, Revision A. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 131 individual 1250 ft x 1250 ft tiles clipped to the DPA, as tiled bare-earth DEMs and as tiled all-return MSHRs; all tiled to the same 1250 ft x 1250 ft schema.

Ground Conditions: Lidar was collected in February/March 2025, 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, Sanborn Map Company, Inc., established a total of 40 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area.

This data was provided to the NOAA Office for Coastal Management (OCM) by the Chesapeake Bay NERR (CBNERRVA) for the purpose of making the data publicly available for custom and bulk downloads from the NOAA Digital Coast Data Access Viewer.

Lineage Statement:
This data was provided to the NOAA Office for Coastal Management (OCM) by the Chesapeake Bay NERR (CBNERRVA), for the purpose of making the data publicly available for custom and bulk downloads from the NOAA Digital Coast Data Access Viewer.

Process Steps:

• 2025-01-01 00:00:00 - The boresight was completed prior to project execution. The following steps describe the Raw Data Processing process: 1) Technicians processed the raw data to LAS format flight lines using the final GNSS/IMU solution. This LAS data set was used as source data for lidar matching. 2) Technicians utilized commercial and proprietary software packages to analyze how well flight line overlaps match for the entire lift and adjusted as necessary until the results met the project specifications. 3) Once all lifts were completed with lidar matching, the technicians checked and corrected the vertical misalignment of all flight lines and also the matching between data and ground truth. The relative accuracy was less than or equal to 6 cm RMSEz within individual swaths and less than or equal to 8 cm RMSEz or within swath overlap (between adjacent swaths). 4) The technicians ran a final vertical accuracy check of the flight lines against the surveyed check points after the z correction to ensure the requirement of NVA = 19.6 cm 95% Confidence Level (Required Accuracy) was met. Point classification was performed according to USGS Lidar Base Specification, and breaklines were collected for water features. Bare-earth DEMs were exported from the classified point cloud using collected breaklines for hydroflattening.
• 2025-01-01 00:00:00 - LAS Point Classification: The point classification is performed as described below: Bare-earth points are extracted from the point cloud using automated processes in Terrascan. Then the bare-earth surface is manually reviewed to ensure correct classification on the Class 2 (Ground) points. All points determined to be in water are then classified to Class 9 (Water). No overlap points were classified or flagged, and all withheld points were flagged using Terrascan. All data was manually reviewed and any remaining artifacts removed using functionality provided by LP360, TerraScan and TerraModeler. Global Mapper was used as a final check of the bare-earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files. Sanborn Map Company, Inc. uses proprietary software to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.
• 2025-01-01 00:00:00 - Data was tested at 0.26 meter aggregate nominal pulse spacing and at 14.8 aggregate points per meter. The aggregate nominal pulse spacing was tested on classified tiled LAS using geometrically reliable first-return points without overlap. ANPS was tested using Delaunay Triangulation that produced average point spacing between all nearest neighbors.
• 2025-01-01 00:00:00 - Maximum Surface Height Rasters were produced as ancillary data from the classified lidar point cloud in order to evaluate the withheld bit flag proof of performance for points that cannot be reasonably interpreted as valid surface returns. These were produced using all returns, withheld flagged points excluded, and using the highest elevation point value from each pixel. These rasters are 32-bit, floating point format and delivered as GeoTIFF files per tile. Cell size of the MSHR is 2 ft. MSHR are generated from the point cloud data and will not be altered after creation nor will there be further maintenance on this product.
• 2025-01-01 00:00:00 - Swath Separation Imagery was produced for the entire project area. Swath separation images use color-coding to illustrate differences in elevation (z-) values where swaths overlap. The color-coded images are semi-transparent and overlay the lidar intensity image. They are ancillary data used as visual aids to more easily identify regions within point cloud datasets that may have suspect interswath alignment or other geometric issues. Imagery was created using last returns with all classification and bit flags, except for noise and withheld bit flag are included. Images are derived from a TIN and have a 50% transparent RGB layer over lidar intensity. Color intervals are as follows: 0-8cm, green; 8-16cm, yellow; >16cm, red. These files were produced as GeoTIFF tiles using a cell size of 2 ft. SSI are generated from the point cloud data and will not be altered after creation nor will there be further maintenance on this product.
• 2026-04-20 00:00:00 - The NOAA Office for Coastal Management (OCM) received 132 las files from the CBNERRVA. The files were in VA State Plane South NAD83(HARN) feet coordinates and the elevations were in NAVD88 (GEOID18) feet. The LAS files had these classifications: 1 = unclassified; 2 = ground (or Bare Earth); 7 = low noise; 9 = water; 17 = bridges; 18=high noise. NOAA OCM processed all of the point classes to the Digital Coast Data Access Viewer (DAV). OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. Internal OCM scripts were run to check the number of points by classification and by flight ID and the gps, elevation, and intensity ranges. 2. Internal OCM scripts were run on the LAS files to: a. Convert from orthometric (NAVD88) elevations to ellipsoid elevations using the GEOID18 model b. Convert from VA State Plane South NAD83(HARN) feet coordinates to geographic coordinates c. Convert from elevations in feet to elevations in meters

Data is available online for bulk and custom downloads.

Data is backed up to cloud storage.