Data Management Plan

Digital Aerial Solutions, LLC (DAS) was tasked to collect and process a Light Detection And Ranging (LiDAR) derived elevation dataset for Jean Lafitte and Barataria area located in South of New Orleans, Louisiana. The Jean Lafitte LiDAR survey encompasses 77 square miles and Barataria LiDAR survey encompasses approximately 1408 square miles. Aerial LiDAR data was collected utilizing an ALS60 Sensor. The ALS60 is a discrete return topographic LiDAR mapping system manufactured by Leica Geosystems. LiDAR data collected for the Jean Lafitte survey area has a nominal pulse spacing of 1m and Barataria has a nominal pulse spacing of 2 meters, and includes up to 4 discrete returns per pulse, along with intensity values for each return. The acquisition mission for the Jean Lafitte and Barataria LiDAR survey was coordinated to be acquired in 1 week. Collection began on March 5th 2013 and was completed on March 8th, 2013.

LiDAR datasets were post processed to generate elevation point cloud swaths for each flight line. Deliverables include the point cloud swaths, tiled point clouds classified by land cover type, breaklines to support hydro-flattening of digital elevation models (DEM)s, and bare-earth DEM tiles. Point cloud deliverables are stored in the LAS version 1.2 format, point data record format 1. The tiling scheme for tiled deliverables is a 1500 meter x 1500 meter grid aligned and named according the US National Grid conventions. All deliverables were generated in conformance with the U.S. Geological Survey National Geospatial Program Guidelines and Base Specifications, Version 1.

The NOAA Office for Coastal Management (OCM) downloaded 125 LA_Jean-Lafitte_2013/ laz files and 1791 USGS_LPC_LA_Barataria_2013_LAS_2015/ laz files from this USGS site: ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/ and processed the data to the Data Access Viewer (DAV) and https. The two project areas were downloaded and processed at different times.

Hydro breaklines are also available. These data are available for download at the link provided in the URL section of this metadata record. Please note that these products have not been reviewed by the NOAA Office for Coastal Management (OCM) and any conclusions drawn from the analysis of this information are not the responsibility of NOAA or OCM.

Process Steps:

• 2013-03-07 00:00:00 - The ABGPS, inertial measurement unit (IMU), and raw scans are collected during the LiDAR aerial survey. The ABGPS monitors the xyz position of the sensor and the IMU monitors the orientation. During the aerial survey, laser pulses reflected from features on the ground surface are detected by the receiver optics and collected by the data logger. GPS locations are based on data collected by receivers on the aircraft and base stations on the ground. The ground base stations are placed no more than 40 km radius from the flight survey area.
• 2013-03-25 00:00:00 - The ABGPS, IMU, and raw scans are integrated using proprietary software developed by Leica Geosystems called IPAS Pro (Version 1.35). These LiDAR data are then output to a ASPRS Version 1.2 LAS binary format using Leica Geosystems ALSPP post-processing software (Release 2.74 Build #9 ) The LAS version 1.2 file format can be easily transferred from one file format to another. It is a binary file format that maintains information specific to the LiDAR data (return number, intensity value, xyz, etc.). The header file for each dataset is complete as defined by the LAS 1.2 specification.
• 2013-06-20 00:00:00 - The unedited data are classified to facilitate the application of the appropriate feature extraction filters. Combinations of proprietary filters are applied as appropriate for the production of bare earth digital elevation models (DEMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature extraction filters are used to produce elevation height surfaces.
• 2013-07-08 00:00:00 - Filtered and edited data are subjected to rigorous QA/QC, A series of quantitative and visual procedures are employed to validate the accuracy and consistency of the filtered and edited data. Ground control is established by DAS and GPS-derived ground control points (GCPs) in various areas of dominant and prescribed land cover. These points are coded according to land cover, surface material, and ground control suitability. A suitable number of points are selected for calculation of a statistically significant accuracy assessment, as per the requirements of the National Standard for Spatial Data Accuracy. A spatial proximity analysis is used to select edited LiDAR data points within a specified distance of the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error, and adequate sample size. Accuracy validation and evaluation is accomplished using proprietary software to apply relevant statistical routines for calculation of Root Mean Square Error (RMSE) and the National Standard for Spatial Data Accuracy (NSSDA), according to Federal Geographic Data Committee (FGDC) specifications.
• 2015-01-26 00:00:00 - The NOAA Office for Coastal Management (OCM) downloaded the laz format files for the Jean Lafitte project area from USGS via an FTP online repository. The files contained lidar elevation and intensity measurements. The data were in UTM Zone 15, NAVD88 (orthometric) heights in meters. OCM performed the following processing for data storage and Digital Coast provisioning purposes: 1. The data were converted from UTM coordinates to geographic coordinates. 2. The data were converted from NAVD88 (orthometric) heights in meters to GRS80 (ellipsoid) heights in meters using Geoid 09. 3. Erroneous elevations were removed. 4. Class 11 points (withheld) were reclassed to Class 15 (as needed). 5. The LAS data were sorted by latitude and the headers were updated.
• 2018-10-05 00:00:00 - The NOAA Office for Coastal Management (OCM) downloaded 1791 USGS_LPC_LA_Barataria_2013_LAS_2015/ laz files from this USGS site: ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_LA_Barataria_2013_LAS_2015/. The data were in UTM Zone 15 North coordinates and NAVD88 (Geoid09) elevations in meters. The data were classified as: 1 - Unclassified, 2 - Ground, 7 - Low Noise, 9 - Water, 10 - Ignored Ground, 17 - Overlap Ground, 18 - Overlap Default. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes 17 and 18 for the entire project area were switched to match the USGS classification guidelines for overlap default (Class 17) and overlap ground (Class 18). Classes available on the DAV are: 1, 2, 7, 9, 10, 17, 18. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. The LAStools software scripts lasinfo and lasvalidate were run on the laz files to check for errors. 2. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges. 3. The LAStools software script las2las was run to convert the gps time from gps seconds of the week (week 1730) to adjusted gps time. 4. The LAStools software script las2las was run on the files for the entire project area to switch the classifications of points that were classified as 17 to 18 and those that were classified as 18 to 17 to match the USGS classification guidelines for overlap default (Class 17) and overlap ground (Class 18). 5. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid 09 model, to convert from UTM Zone 15 North coordinates in meters to geographic coordinates, to assign the geokeys, to sort the data by gps time and zip the data to database and to http.

Data is available for bulk and custom downloads.