Data Management Plan

LiDAR data is a remotely sensed high resolution elevation data collected by an airborne platform. The LiDAR sensor uses a combination of laser range finding,

GPS positioning, and inertial measurement technologies. The LiDAR systems collect data point clouds that are used to produce highly detailed Digital

Elevation Models (DEMs) of the earth's terrain, man-made structures, and vegetation. The task required the LiDAR data to be collected at a nominal pulse

spacing (NPS) of 1.0 meter. The final products include full classified LAS, hydrologically flattened four (4) foot pixel raster DEM's of the bare earth

surface in IMG Format, and hydrologically flattened breaklines in gdb format. Links to the hydrologically flattened 4 foot pixel raster bare earth DEMs and

the hydrologically flattened breaklines are provided in the Supplemental Information section below.

This metadata record describes the classified LAS files. The classifications of lidar data available from the Digital Coast are:

1 Unclassified

2 Ground

7 Noise

9 Water

10 Ignored Ground

17 Overlap Unclassified

18 Overlap Ground

This lidar data set also includes lidar intensity values. Intensity information is captured from the reflective surface pulse and indicates the relative energy

returned to the sensor, as compared to the energy transmitted. The intensity image is not calibrated or normalized but indicates differences in energy absorption due to the interaction of the surface materials with laser energy, at the wavelength transmitted by the sensor.

This lidar data set covers 1455 sq miles in Baldwin, Hancock, Morgan, and Putnam counties in Georgia. The data were collected Dec 19, 22, 28, 30, 2012 and

January 4, 5, 2013.

The LiDAR data were collected to meet Fundamental Vertical Accuracy (FVA) Root Mean Square Error (RMSE) of 18.0 cm or better at a 95% confidence level,

so that when combined with breaklines, the data adequately supports the generation of two (2) foot FEMA compliant contours. The final LiDAR data were

delivered in 5,000 ft x 5,000 ft tiles using NAD 1983(2011), Georgia State Plane Coordinate System, West Zone, and expressed in US Survey Feet for Morgan

and Putnam Counties. The final LiDAR data was delivered in 5,000 ft x 5,000 ft tiles using NAD 1983(2011), Georgia State Plane Coordinate System, East Zone,

and expressed in US Survey Feet for Baldwin and Hancock Counties. The vertical datum used for this survey is North American Vertical Datum 1988 (NAVD88),

and expressed in US Survey Feet. Upon receipt of the data, the NOAA Office for Coastal Management (OCM) converted the data for Digital Coast storage purposes.

The data were converted to geographic coordinates and ellipsoid heights, expressed in meters.

Process Steps:

• 2012-12-20 00:00:00 - Using an Optech Gemini LiDAR system, 142 flight lines of high density data, at a nominal pulse spacing (NPS) of 1.0 meter, were collected over Morgan, Hancock, Putnam, and Baldwin Counties, GA (approximately 1455 square miles). Multiple returns were recorded for each laser pulse along with an intensity value for each return. A total of thirteen (13) missions were flown on December 19, 22, 28, 30 in 2012 and January 4 and 5 in 2013. The geoid used to reduce satellite derived elevations to orthometric heights was GEOID12A. The horizontal datum used for this survey is NAD 1983 (2011), Georgia State Plane Coordinate System, West Zone, and expressed in US Survey Feet for Morgan and Putnam Counties. The horizontal datum used for this survey is NAD 1983 (2011), Georgia State Plane Coordinate System, East Zone, and expressed in US Survey Feet for Baldwin and Hancock Counties. The vertical datum used for this survey is North American Vertical Datum 1988 (NAVD88), and expressed in US Survey Feet. Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface for each flight line.
• 2012-01-01 00:00:00 - The Optech Gemini LiDAR system calibration and performance is verified on a periodic basis using Woolpert's calibration range. The calibration range consists of a large building and runway. The edges of the building and control points along the runway have been located using conventional survey methods. Inertial measurement unit (IMU) misalignment angles and horizontal accuracy are calculated by comparing the position of the building edges between opposing flight lines. The scanner scale factor and vertical accuracy is calculated through comparison of LiDAR data against control points along the runway. Field calibration is performed on all flight lines to refine the IMU misalignment angles. IMU misalignment angles are calculated from the relative displacement of features within the overlap region of adjacent (and opposing) flight lines. The raw LiDAR data is reduced using the refined misalignment angles.
• 2012-12-20 00:00:00 - Once the data acquisition and GPS processing phases are complete, the LiDAR data was processed immediately to verify the coverage had no voids. The GPS and IMU data was post processed using differential and Kalman filter algorithms to derive a best estimate of trajectory. The quality of the solution was verified to be consistent with the accuracy requirements of the task order.
• 2012-12-20 00:00:00 - The individual flight lines were inspected to ensure the systematic and residual errors have been identified and removed. Then, the flight lines were compared to adjacent flight lines for any mismatches to obtain a homogenous coverage throughout the project area. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing first and only as well as last of many LiDAR returns. This process determined bare-earth points (Class 2), noise (Class 7), water (Class 9) ignored ground (Class 10), unclassified data (Class 1), overlap default (Class 17), and overlap ground (Class 18). The bare-earth (Class 2 - Ground) LiDAR points underwent a manual QA/QC step to verify that artifacts have been removed from the bare-earth surface. The surveyed ground control points are used to perform the accuracy checks and statistical analysis of the LiDAR dataset.
• 2014-03-15 00:00:00 - The NOAA Office for Coastal Management (OCM) received the files in las format. The files contained lidar elevation and intensity measurements. The data were in Georgia State Plane coordinates, NAVD88 elevations, and US Survey feet vertical units. OCM performed the following processing for data storage and Digital Coast provisioning purposes: 1. The data were converted from Georgia State Plane (Zones East (FIPs 1011) and West (FIPS 1002)) coordinates to geographic coordinates. 2. The data were converted from NAVD88 heights to ellipsoid elevations using Geoid12A. 3. The data were converted from US Survey Feet vertical units to meters vertical units. 4. The data were filtered for elevation outliers. 5. The data were zipped to laz format.

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2619

This data set is dynamically generated based on user-specified parameters.;