2009-2010 USACE Vicksburg District Lidar: Mississippi River Delta

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Date that the source FGDC record was last modified.

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

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LiDAR points were used to produce the deliverables. | Source Geospatial Form: digital data | Type of Source Media: hard drive

Applanix software was used in the post processing of the airborne GPS and inertial

data that is critical to the positioning and orientation of the sensor during all

flights. POSPac MMS provides the smoothed best estimate of trajectory (SBET) that

is necessary for Optech's post processor to develop the point cloud from the LiDAR

missions. The point cloud is the mathematical three dimensional collection of all

returns from all laser pulses as determined from the aerial mission. At this point

this data is ready for analysis, classification, and filtering to generate a bare

earth surface model in which the above ground features are removed from the data

set. The point cloud was manipulated within the Optech or Leica software; GeoCue,

TerraScan, and TerraModeler software was used for the automated data classification,

manual cleanup, and bare earth generation from this data. Project specific macros

were used to classify the ground and to remove the side overlap between parallel

flight lines.

All data was manually reviewed and any remaining artifacts removed using

functionality provided by TerraScan and TerraModeler.

Class 2 LIDAR was used to create a bare earth surface model. The surface model

was then used to heads-up digitize 2D breaklines of inland streams and rivers

with a 30 foot nominal width and Inland Ponds and Lakes of 0.25 acres or greater.

Elevation values were assigned to all Inland Ponds and Lakes using TerraModeler

functionality.

Elevation values were assigned to all Inland streams and rivers using Photo Science

proprietary software.

All Class 2 LIDAR data inside of the collected breaklines were then classified to

Class 9 using TerraScan macro functionality.

The breakline files were then translated to ESRI Shapefile and ARC Generate format

using ESRI conversion tools.

Breaklines were used to reclassify lakes, ponds, and inland drains.

Data was then run through additional macros to ensure deliverable classification

levels matching LAS ASPRS Classification structure. GeoCue functionality was then

used to ensure correct LAS Version. In house software was used as a final QA/QC

check to provide LAS Analysis of the delivered tiles.

Buffered LAS files were created in GeoCue to provide overedge to the DEM creation.

These tiles were then run through automated scripting within ArcMap and were combined

with the Hydro Flattened Breaklines to create the 5' DEM. Final DEM tiles were

clipped to the tile boundary in order to provide a seamless dataset.

A manual QA review of the tiles was completed in ArcMap to ensure full coverage with

no gaps or slivers within the project area.

The NOAA Office for Coastal Management (OCM) received the files in laz format. The files contained LiDAR

elevation and intensity measurements. The data were in Mississippi State Plane West (2301, feet) coordinates and NAVD88 (Geoid03) vertical datum (feet).

OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The data were converted from State Plane (2301) coordinates to geographic coordinates.

2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid03.

3. The data were cleaned of bad elevations above 150 m and below 0 m, assumed to be errors points/noise.

4. The data were sorted by time and zipped to laz format.