Data Management Plan

These files contain classified topo/bathy lidar data generated from data collected by the Coastal Zone Mapping and Imaging Lidar (CZMIL) system. CZMIL integrates a lidar sensor with simultaneous topographic and bathymetric capabilities, a digital camera and a hyperspectral imager on a single remote sensing platform for use in coastal mapping and charting activities. Native lidar data is not generally in a format accessible to most Geographic Information Systems (GIS). Specialized in-house and commercial software packages are used to process the native lidar data into 3-dimensional positions that can be imported into GIS software for visualization and further analysis.

The data was received by the NOAA Office for Coastal Management (OCM) with the horizontal positions, provided in decimal degrees of latitude and longitude, referenced to the North American Datum of 1983 National Adjustment of 2011 (NAD83 (2011)). Vertical positions were referenced to the NAD83 (2011) ellipsoid and provided in meters. The 3-D position data are sub-divided into a series of LAS files, which are tiled into 1-km by 1-km boxes defined by the Military Grid Reference System.

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 also available from the NOAA Digital Coast. A link to this data is provided in the URL section of this metadata record. DEMs at a 1 meter grid spacing, created from all classifications, are available by request at coastal.info@noaa.gov.

Lineage Statement:
CZMIL data is processed from raw lidar waveforms to point clouds using the CZMIL HydroFusion software package. Point clouds are then classified and edited in industry-standard software packages. Derivative data products are generated through the application of gridding and contouring algorithms in a GIS environment. The data processing workflow, including software packages, algorithms and parameters are provided in detail, herein this metadata as Process Steps.

Process Steps:

• 2019-09-07 00:00:00 - These data were collected using the CZMIL system. It is owned and operated by the U.S. Army Corps of Engineers (USACE). The system collects topobathy lidar data at 10 kHz and RGB imagery at 2 Hz. A CASI-1500 hyperspectral line scanner is integrated with the system as well. Aircraft position, velocity and acceleration information are collected through a combination of NovAtel and POS A/V 610 equipment. All raw data streams are transferred to the office for downloading and processing in CZMIL's HydroFusion software. Aircraft position data are processed using POSPac software and the results are combined with the lidar data to produce 3-D positions for each lidar shot. Upon inspection and QA/QC in the software packages Fledermaus and PFM_ABE, anomalous data are flagged as invalid and have the withheld bit set.
• 2022-06-13 00:00:00 - LAS files are imported into TerraScan V13 module within MicroStation V8i, classifies valid topobathy data as ground points (2) and unclassified points (1), and valid bathymetric points (29). Upon completion the macro, the classification results undergo quality control and any misclassified points are manually edited. In areas of dense vegetation the bare earth ground points might be incorrectly classified due to the inability of the laser to penetrate the canopy and reach the bare ground. In these areas, JALBTCX defaults to the algorithm's "ground" surface instead of manually reclassifying those points. They are partitioned into a series of 1-km delivery boxes, one Classified LAS file per box. The format of the file is LAS version 1.2. Data are classified as 1 (valid non-ground topographic data), 2 (valid ground topographic data), and 29 (valid bathymetric data). The National Geodetic Survey's (NGS) GEOID12B model is used to transform the horizontal positions from UTM to Geographic coordinates referenced to the North American Datum of 1983 National Adjustment of 2011 (NAD83 2011). The files are then compressed with the open-source LASzip utility, which is part of the LAStools package (LAStools, "Efficient LiDAR Processing Software" (version 210720, licensed)), obtained from http://rapidlasso.com/LAStools.
• 2023-10-18 00:00:00 - The NOAA Office for Coastal Management (OCM) received 747 (NY - 446, OH - 57, PA - 244) laz files from USACE JALBTCX for the Lake Erie coastline in New York, Ohio, and Pennsylvania. The lidar data had elevation and intensity measurements. The data were in geographic coordinates (NAD83 2011) and ellipsoid elevations in meters. The data were classified as: 1 - Unclassified, 2 - Ground, 29 - Bathymetric Point. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2, 29. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges. 2. Internal OCM scripts were run on the laz files to assign the geokeys, to sort the data by gps time and zip the data to database and to AWS S3.

JALBTCX evaluates final data coverage using techniques that are common to the lidar industry. These techniques are performed in a 3D environment for visual review of the final data coverage and verification of data alongside lidar waveforms and imagery collected concurrent with the lidar. Data reviewers perform checks to verify (1) extreme high and/or low elevation values have been invalidated, (2) elevations in areas of swath overlap are internally consistent, (3) binned standard deviation values meet CZMIL specifications, (4) point cloud classifications are valid, and (4) CZMIL processing modes are valid.

Data is available online for bulk and custom downloads.

Data is backed up to tape and to cloud storage.