2016 - 2017 NRCS Lidar: 17 Counties, GA

Product: These lidar data are processed classified LAS 1.4 files, formatted to individual 5,000-foot x 5,000-foot pilot tiles; used to create intensity images, 3D breaklines, hydro-flattened DEMs, and building footprints as necessary.

Geographic Extent: Seventeen whole and partial counties in Georgia, covering approximately 6,851 total square miles

GA_Georgia_A1 (West AOI) covering approximately 5364 square miles in the following counties: Brooks, Colquitt, Grady, Lamar, Lee, Marion, Meriwether, Mitchell, Pike, Schley, Spalding, Sumter, Talbot, Thomas, Upson, Worth

GA_Georgia_A2 (East AOI) covering approximately 1198 square miles in the following counties: Burke, Jenkins

GA_Georgia_A3 (West AOI) covering approximately 289 square miles in the following county: Calhoun

Dataset Description of the Original Data: Georgia Counties 2016 QL2 Lidar project called for the planning, acquisition, processing, and derivative products of lidar data to be collected at a 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. The data for counties in the eastern AOI were developed based on a horizontal projection/datum of NAD83 (2011), State Plane Georgia East Zone, US survey feet and vertical datum of NAVD88 (GEOID12B), US survey feet. The data for counties in the western AOIs were developed based on a horizontal projection/datum of NAD83 (2011), State Plane Georgia West Zone, US survey feet and vertical datum of NAVD88 (GEOID12B), US survey feet. Lidar data was delivered as flightline-extent unclassified LAS swaths, as processed Classified LAS 1.4 files formatted to individual 5,000-foot x 5,000-foot tiles, as tiled intensity imagery, and as tiled bare earth DEMs; all tiled to the same 5,000-foot x 5,000-foot schema. Continuous breaklines were produced in Esri file geodatabase format. Building footprints were created in Esri file geodatabase format.

Ground Conditions: Lidar was partially collected in February and March of 2016, while no snow was on the ground and rivers were at or below normal levels. Due to unfavorable conditions the remainder of the data was collected in January and February of 2017.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) hosted by USGS on Amazon Web Services.

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create intensity images, breaklines and raster DEMs. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened digital elevation models (DEMs) with a 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, intensity images, 3D breaklines, hydro-flattened DEMs, and building footprints as necessary.

USGS Contract No. G10PC00016 CONTRACTOR: Quantum Spatial, Inc. SUBCONTRACTOR: Aerial Surveys International, LLC. Lidar data were acquired by Aerial Surveys International, LLC. All follow-on processing was completed by the prime contractor.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Specification v1.2",

"ldrsens" : "Optech Orion H300",

"ldrmaxnr" : "5",

"ldrnps" : "0.69",

"ldrdens" : "2.19",

"ldranps" : "0.69",

"ldradens" : "2.19",

"ldrfltht" : "1700",

"ldrfltsp" : "140",

"ldrscana" : "38",

"ldrscanr" : "52.0",

"ldrpulsr" : "225",

"ldrpulsd" : "4",

"ldrpulsw" : "0.41",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1170.17",

"ldrswato" : "30",

"ldrcrs" : "NAD 1983 (2011) State Plane Georgia East Zone US Survey Feet",

"ldrgeoid" : "GEOID12B"

},

"ldraccur" : {

"ldrchacc" : "0",

"rawnva" : "0.075",

"rawnvan" : "146"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit",

"lasolap" : "Swath "overage" points were identified in these files using the standard LAS overlap bit",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare-Earth Ground"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Buildings"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "In-land Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

}

}}

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

Data is available online for bulk and custom downloads.

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

The required accuracy testing was performed on the LiDAR dataset (both the LiDAR point cloud and derived DEM's according to the USGS LiDAR Base Specification Version 1.2 (2014). In this document, horizontal coordinates for ground control and QA points for all LiDAR classes are reported in NAD83 (2011) State Plane Georgia West and East Zones, US survey feet; NAVD88 (GEOID12B), US survey feet. The values listed below were based upon the portion of the dataset that was collected from February 28 - March 18, 2016, not the entirety of the dataset (the remainder of the dataset was collected in January and February of 2017).

The project specifications require that only Non-Vegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The required accuracy (ACCz) is: 19.6 cm at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 10 cm in the bare earth and urban land cover classes. The NVA was tested with 5 checkpoints in the GA West - Small AOI, 22 checkpoints in the GA West Spring 2016 AOI, and 40 checkpoints in the GA East AOI, all located in bare earth and urban (non-vegetated) areas. These check points were not used in the calibration or post processing of the lidar point cloud data. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See the report listed in the URL section of this metadata record for additional accuracy information.

GA_Georgia_A1 (West Spring AOI) covering approximately 5364 square miles in the following counties: Brooks, Colquitt, Grady, Lamar, Lee, Marion, Meriwether, Mitchell, Pike, Schley, Spalding, Sumter, Talbot, Thomas, Upson, Worth

NVA RMSE = 4 cm

VVA = 12 cm at the 95th Percentile

GA_Georgia_A2 (East AOI) covering approximately 1198 square miles in the following counties: Burke, Jenkins

NVA RMSE = 3.7 cm

VVA = 9.4 cm at the 95th Percentile

GA_Georgia_A3 (West Small AOI) covering approximately 289 square miles in the following county: Calhoun

NVA RMSE = 3 cm

VVA = 4.6 cm at the 95th Percentile

These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Data covers the entire area specified for this project.

Data is backed up to cloud storage.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS Entwine Point Tiles (EPT) hosted on Amazon Web Services (AWS) into the Digital Coast Data Access Viewer (DAV). The DAV accesses the point cloud as it resides on AWS under the usgs-lidar-public-container.