2010 USACE NCMP Topobathy Lidar: Gulf Coast - A (LA, MS)

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Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document.

Information on the NOAA Office for Coastal Management (OCM)

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.

This graphic displays the footprint for this lidar data set.

These data were collected using the CHARTS system. It is owned by the Naval Oceanographic Office and operated through contract. The system collects topographic lidar data at 9kHz, bathymetric lidar data at 1kHz and RGB imagery at 1Hz. 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 410 equipment. All raw data streams are transferred to the office for downloading and processing in SHOALS GCS 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. PFM_ABE's chartsLAS module then converts all valid data from ellipsoid to orthometric heights based on the NGS' GEOID03 model and exports topographic data as a series of LAS files with a single file per flightline per 5km box.

The flightline LAS files are imported into the TerraScan V11 module within MicroStation V8.0. The resulting LAS files are thinned to eliminate duplicate points. A customized classification macro is used to distinguish ground points (2) and unclassified points (1). The classification results are QC'd and any misclassified points are manually edited. In areas of dense vegetation the bare 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. The points are exported to an ASCII file containing the following fields: longitude, latitude, elevation (orthometric), intensity, classification, mirror angle, time (GPS time), number of echos, and echo number. The ASCII file is converted to LAS with the txt2las code from LAStools (http://www.cs.unc.edu/~isenburg/lastools/). The resulting topographic las files and bathymetric ASCII were then loaded into Geocue to produce on single las file representing both valid bathymetry and topography in ellipsoid.

The NOAA Office for Coastal Management (OCM) received 21 laz files in las 1.2 format in 2018 from JALBTCX. These files are a subset of the data available in the 2010 USACE NCMP Topobathy Lidar: Gulf Coast (LA, MS) data set. These data are classified as 1 - unclassifed, 2 - ground, and 29 - bathymetry. The files contained lidar elevation measurements for the project area. Horizontal positions were provided in geographic coordinates, referenced to the North American Datum of 1983. Vertical positions were provided in ellipsoid elevations and in meters. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. Assigned the geokeys, sorted the data by gps time and copied the data to database and to https.