Data Management Plan

These are Digital Elevation Model (DEM) data for the north and south sections for the 2016 Mississippi Lidar QL2 Lidar project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create a hydro-flattened raster DEM.

North AOI (Northeast MS):

2949 individual 1500 m x 1500 m tiles, 1 m grid spacing

Northern AOI counties: Alcorn, Benton, Itawamba, Lee, Lowendes, Marshall, Monroe, Prentiss, Tippah, Tishomingo, and Union, covering approximately 2318 square miles of the 3825 total square mile project area.

The data for counties in the northern AOI were developed based on a horizontal projection/datum of NAD83 (2011) UTM Zone 16, meters and vertical datum of NAVD1988 (Geoid 12B), meters.

In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Quantum Spatial, Inc. established a total of 59 ground control points that were used to calibrate the lidar to known ground locations established throughout the Mississippi project area. One point was removed due to drastic change in the area. An additional 96 independent accuracy checkpoints, 56 in Bare Earth and Urban landcovers (56 NVA points), 40 in Forested, Shrubs, and Tall Weeds categories (40 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

Vertical Accuracy = 4.9 cm RMSE

South AOI (Camp Shelby):

1791 individual 5,000-foot x 5,000-foot tiles, 2,5 ft grid spacing

Southern AOI counties: Forrest, Greene, Lamar, and Perry, covering approximately 1507 square miles of the 3825 total square mile project area.

The data for counties in the southern AOI were developed based on a horizontal projection/datum of NAD83 (2011) State Plane Mississippi East Zone, US survey feet and vertical datum of NAVD1988 (Geoid 12B), US survey feet. NOAA OCM converted the elevations from feet to meters.

In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Quantum Spatial, Inc. established a total of 38 ground control points that were used to calibrate the lidar to known ground locations established throughout the Mississippi project area. An additional 78 independent accuracy checkpoints, 43 in Bare Earth and Urban landcovers (43 NVA points), 35 in Forested, Shrubs, and Tall Weeds categories (35 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. One point was removed from the NVA calculations due to drastic change in the area.

Vertical Accuray = 4.6 cm RMSE

Dataset Description: The Mississippi 2016 Aerial LiDAR Mapping project called for the planning, acquisition, processing and derivative products of LIDAR data to be collected at an aggregate nominal pulse spacing (NPS) of 0.7 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LIDAR Specification, Version 1.2. LiDAR data was delivered in RAW flight line swath format. Corresponding 2.5-foot intensity images in GeoTIFF format and 2.5-foot bare-earth DEM files in ERDAS .IMG format were created with the same tile schema. Tiles names follow the US National Grid naming schema. Hydro-flattened breaklines were produced in Esri file geodatabase format. Continuous contours with a 1-foot interval were produced in Esri file geodatabase format.

Ground Conditions: Lidar was collected in winter of 2016, while no snow was on the ground and rivers were at or below normal levels

The NOAA Office for Coastal Management (OCM) received the data for processing of the data to the Data Access Viewer (DAV) and https. In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEMs were created from, are also available. These data are available for custom download at the link provided in the URL section of this metadata record. 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:

• 2016-01-01 00:00:00 - LAS Point Classification: The point classification is performed as described below. The bare earth surface is then manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through heads-up digitization. All ground (ASPRS Class 2) lidar data inside of the Lake Pond and Double Line Drain hydro-flattened breaklines were then classified to Water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 3 feet was also used around each hydro-flattened feature to classify these ground (ASPRS Class 2) points to Ignored ground (ASPRS Class 10). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (ASPRS Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to approved classes by USGS. The overlap data was classified using standard LAS overlap bit. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS through numerous conference calls and pilot study areas. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper us used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Quantum Spatial, Inc. proprietary software was used 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.
• 2016-01-01 00:00:00 - Hydro Flattened Raster DEM Process: Class 2 (Ground) lidar points in conjunction with the hydro breaklines were used to create a 1 meter hydro-flattened raster DEM. Using automated scripting routines within ArcMap, an ERDAS Imagine .IMG file was created for each tile. Each surface is reviewed using Global Mapper to check for any surface anomalies or incorrect elevations found within the surface.
• 2018-07-09 00:00:00 - The NOAA Office for Coastal Management (OCM) received the DEM files from MS State University. There were 2 AOIs in the project, a northern AOI and a southern AOI. The data in the northern AOI were in UTM Zone 16 North coordinates and NAVD88 (Geoid12B) elevations in meters at a 1m grid spacing. The data in the southern AOI were in MS State Plane East, US Survey Feet coordinates and NAVD88 (Geoid12B) elevations in feet at a 2.5 ft grid spacing. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. The files in the southern AOI were converted from elevations in feet to meters 2. The files were copied to https.

Data is available online for bulk and custom downloads.