2006 South Carolina DNR Lidar: Aiken County

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Simple download of data files.

This graphic shows the lidar coverage for the 2006 DNR lidar project covering Aiken County, SC.

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.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

The LiDAR data acquisition was executed in five sessions, on March 15, 16 & 17, 2006, using a Leica ALS50 LiDAR System. Specific details about the ALS50 system are included in Section 4 of this report.

The three airborne GPS (ABGPS) base stations supporting the LiDAR acquisition were located on 1) a NGS SAC monumented control point inside Bush Field Airport (AGS), point AA2799, 2) a point inside the county "RS_0001" and 3) a another point nearby "RS_0002". Dual Frequency data was logged continuously for the duration of each LiDAR flight mission at a one-second sampling rate.

The LiDAR data was acquired using 2 ALS50's onboard 2 Cessna T404's. The ALS50 LiDAR system, developed by Leica Geosystems of Boston, Massachusetts, includes the simultaneous first, intermediate and last pulse data capture module, the extended altitude range module, and the target signal intensity capture module. The system software is operated on a P-400 Diagnostic System Laptop Computer aboard the aircraft.

Woolpert performed ABGPS surveying during the LiDAR mission to derive the flight trajectory at a half-second interval. ABGPS is a critical factor in LiDAR data collection. As such, we spent considerable time developing flight windows around the satellite constellation. We also developed multiple base stations to provide redundancy and to reduce ionospheric and atmospheric errors due to distance separation between the aircraft and the base stations.

At a minimum, two base stations were in operation for every LiDAR acquisition session, operating at a half-second sampling rate. Final adjusted control point values were used to process the LiDAR data. The survey report includes extensive data about the procedures and results for the ground control survey.

As a continuing quality control measure, data was downloaded each evening in the field to verify a strong GPS solution and then refined in-house to determine final trajectories.

A base-station control survey was performed to provide uniformity and to ensure consistency between the ground control and Airborne GPS. All ground control surveys were performed to achieve accuracies consistent with a second-order, class I horizontal (meets or exceeds 1:50,000) and third-order vertical survey as outlined in Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques, Version 5.0, of August 1, 1989, published by the Federal Geodetic Control Committee (FGCC).

For additional information please view the survey report:https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4822/supplemental/sc2006_DNR_aiken_m4822surveyreport.pdf

URS provided Woolpert 843 polygons indicating areas to be corrected. In response, Woolpert provided an ESRI shapefile that identifies 3 categories: CORRECTED, EDIT-UNNEEDED and SWAMP_TREE_AREA. Of the 843 edit areas provided by URS, Woolpert corrected 683 and left 160 unchanged based on review and/or inclusion of breaklines.

Woolpert resubmitted the LiDAR data to URS on Sept 14, 2006. On October 4, 2006 Woolpert received comments from URS that additional editing was still required. Woolpert agreed to review all the bridge locations within the detailed study area and make the appropriate corrections. Woolpert than resubmitted the LiDAR data on November 4, 2006 and it was accepted on November 29, 2006.

The NOAA Office for Coastal Management (OCM) received the files in laz format from SCDNR via an FTP online repository. The files contained lidar elevation and intensity measurements. The data were in State Plane, NAVD88 (orthometric) heights in meters. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The data were converted from state plane 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. The LAS data were sorted by latitude and the headers were updated.