Short Citation:
Office for Coastal Management, 2021: 2015 Lowndes County (GA) Lidar, https://www.fisheries.noaa.gov/inport/item/48183.

Item Identification

Title: 2015 Lowndes County (GA) Lidar
Short Name: ga2015_lowndes_m4971_metadata
Status: Completed
Publication Date: 2015-12
Abstract:

TASK NAME: NOAA OCM Lidar for Lowndes County, GA with the option to Collect Lidar in Cook and Tift Counties, GA

Lidar Data Acquisition and Processing Production Task

NOAA Contract No. EA133C11CQ0010

Woolpert Order No. 05271

CONTRACTOR: Woolpert, Inc.

This data set is comprised of lidar point cloud data, raster DEM, hydrologic 3-d breaklines, flightline vectors, survey control, project tile index, and project data extent. This task order requires lidar data to be acquired over the Lowndes County, GA area of interest (AOI), and will be acquired as part of this task order. The total area of the Lowndes County, GA AOI is approximately 500 square miles. The lidar data acquisition parameters for this mission are detailed in the lidar processing report for this task order. The lidar data will be acquired and processed under the requirements identified in this task order. 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 0.7 meters. The final products include classified LAS, four (4) foot pixel raster DEMs of the bare-earth surface ESRI Grid Format. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Additional deliverables include hydrologic breakline data, flightline vectors, control data, tile index, lidar processing and survey reports in PDF format, FGDC metadata files for each data deliverable in .xml format. Ground conditions: Water at normal levels; no unusual inundation; no snow.

Original contact information:

Contact Org: Woolpert

Phone: (937) 461-5660

Purpose:

The lidar data will be acquired and processed under the requirements identified in this task order. The data produced for this AOI is intended for use in community decision making, including storm water management applications, such as floodplain mapping.

Notes:

10206

Supplemental Information:

A footprint of this data set may be viewed in Google Earth at:

https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4971/supplemental/ga2015_lowndes_m4971.kmz

The survey report for this project is available at:

https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4971/supplemental/ga2015_lowndes_m4971_lidarreport.pdf

The survey report for this project is available at:

https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4971/supplemental/ga2015_lowndes_m4971_surveyreport.pdf

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords Earth Science > Land Surface > Topography > Terrain Elevation > Topographical Relief Maps
Global Change Master Directory (GCMD) Science Keywords Earth Science > Oceans > Bathymetry/Seafloor Topography > Seafloor Topography
Global Change Master Directory (GCMD) Science Keywords Earth Science > Oceans > Coastal Processes > Coastal Elevation
ISO 19115 Topic Category elevation
None Elevation
None LiDAR
None Model
None Remote Sensing
None Topography/Bathymetry

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords Continent > North America > United States Of America > Georgia
None Georgia
None Lowndes County

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: Unknown
Entity Attribute Overview:

Files in LAZ format (Classifications 1,2,7,9,10,17,18)

Entity Attribute Detail Citation:

none

Distribution Liability:

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

Support Roles

Data Steward

CC ID: 623920
Date Effective From: 2015-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Distributor

CC ID: 623922
Date Effective From: 2015-12
Date Effective To:
Contact (Organization): Office for Coastal Management (OCM)
Address: 2234 South Hobson Avenue
Charleston, SC 29405-2413
URL: https://www.coast.noaa.gov/

Metadata Contact

CC ID: 623923
Date Effective From: 2015-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Point of Contact

CC ID: 623921
Date Effective From: 2015-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 623926
W° Bound: -83.614795
E° Bound: -82.982704
N° Bound: 31.095266
S° Bound: 30.58606

Extent Group 1 / Time Frame 1

CC ID: 623925
Time Frame Type: Range
Start: 2015-03-16
End: 2015-03-27

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4971;

Data Access Constraints:

None

Data Use Constraints:

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.

Distribution Information

Distribution 1

CC ID: 743838
Start Date: 2019-07-01
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4971
Distributor: Office for Coastal Management (OCM) (2015-12 - Present)
File Name: Customized Download
Description:

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

File Type: Zip

Distribution 2

CC ID: 743839
Start Date: 2019-07-01
End Date: Present
Download URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4971
Distributor: Office for Coastal Management (OCM) (2015-12 - Present)
File Name: Bulk Download
Description:

Simple download of data files.

File Type: LAZ

URLs

URL 1

CC ID: 743841
URL: https://coast.noaa.gov/dataviewer
Name: Data Access Viewer
URL Type:
Online Resource
Description:

Online tool for custom data download

URL 2

CC ID: 743843
URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4971/supplemental/ga2015_lowndes_m4971.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz
Description:

This graphic shows the lidar coverage for 2015 lidar acquisition of Lowndes County, GA.

Activity Log

Activity Log 1

CC ID: 623940
Activity Date/Time: 2016-05-23
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 623939
Activity Date/Time: 2017-11-14
Description:

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.

Activity Log 3

CC ID: 717859
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 743840
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Data Quality

Accuracy:

LIDAR full returns were compared with NCGS QA/QC checkpoints using only single and final returns per pulse. A vertical bias was

acquired after airport calibration based on this comparison. For the NC Floodplain Mapping Program, the vertical accuracy for

coastal counties is less than or equal to 20 cm RMSE. For mainland counties, the vertical accuracy of the elevation data is less

than or equal to 25 cm RMSE. More information about the Quality Control reports and a summary of the quality control checks for

each county can be found at http://portal.ncdenr.org/web/lr/geodetic/floodplaininfo.

| Quantitative Value: 20 | Quantitative Test Explanation: Less than or equal to 20 cm RMSE of bare earth LIDAR points compared with independent checkpoints.

Horizontal Positional Accuracy:

Compiled to meet 1.180 feet horizontal accuracy at 95 percent confidence level.; Quantitative Value: 0.359 meters, Test that produced the value: Lidar system specifications are available in the project report

Vertical Positional Accuracy:

Data were compared to independent survey control points to determine fundamental vertical accuracy (FVA). Control points were obtained in categories: Bare Earth Open Terrain, Urban, Tall Weeds and Crops, Brush Lands and Trees, Forested and Fully Grown, and Swamp and accuracy was determined for each.

FVA tested 0.114 meters at 95 percent confidence.

Bare ground DEM tested 0.117 meters at 95 percent confidence.

Urban tested 0.120 meters at 95 percent confidence.

Tall Weeds and Crops Land tested 0.215 meters at 95 percent confidence.

Brushlands and Trees tested 0.335 meters at 95 percent confidence.

Forested and Fully Grown tested 0.144 meters at 95 percent confidence.

Swamp tested 0.172 meters at 95 percent confidence.

Consolidated Vertical Accuracy (CVA) tested 0.280 meters at 95 percent confidence.

Completeness Report:

The full return mass points contain voids where insufficient energy was reflected from the surface to generate a valid return from

the terrain. Voids in the full return mass points tend to occur in water bodies. Wet sand and certain types of vegetation can also

cause voids or anomalous elevations.

Conceptual Consistency:

Data was vertically adjusted based on RMSE and mean difference from control report.

Lineage

Sources

calibrated lidar data

CC ID: 858246
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Woolpert

raw lidar data

CC ID: 858245
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Woolpert

Process Steps

Process Step 1

CC ID: 623910
Description:

Using one Leica Optech Gemini (lidar) system on board a Cessna 310 Titan fixed-wing aircraft, lidar data, at a nominal pulse spacing (NPS) of 0.7 meters, was collected for this task order (approximately 500 square miles). AGL = 6500 feet - Aircraft Speed = 150 Knots, Field of View (Full) = 40 degrees, Pulse Rate = 272.0 kHz, Scan Rate = 41.0 Hz, with an average side lap of 20%. Multiple returns were recorded for each laser pulse along with an intensity value for each return. Five (5) missions were flown between March 16, 2015 and March 27, 2015. One (1) Global Navigation Satellite System (GNSS) Base Station was used in support of the lidar data acquisition. Specific information regarding latitude, longitude, and ellipsoid height to the L1 phase center is included in the lidar processing report. Multiple returns were recorded for each laser pulse along with an intensity value for each return. The lidar data acquisition parameters for this mission are detailed in the lidar processing report for this task order. For all acquired lidar data as part of entire NOAA Lidar for Lowndes County, GA task order, the geoid used to reduce satellite derived elevations to orthometric heights was GEOID12A. Data for the task order is referenced to the StatePlane Zone of Georgia West, North American Datum of 1983 (2011) US Feet, and NAVD88, in US Feet. 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 project. The SBET was used to reduce the lidar slant range measurements to a raw reflective surface for each flight line. The coverage was classified to extract a bare earth digital elevation model (DEM) and separate last returns. The Optech Gemini calibration and system 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.

Process Date/Time: 2015-03-17 00:00:00

Process Step 2

CC ID: 623911
Description:

Ground control and QAQC control point survey was performed by Woolpert surveyors, to support the NOAA Lidar for Lowndes County, GA project. All surveys were performed in such a way as to achieve ground control that supports lidar data at 9.25 cm RMSE accuracy and satisfy a local network accuracy of 5 cm at a 95% confidence level. All ground control survey field activities took place from 03/16/2015 thru 03/23/2015. Woolpert collected control data for data processing as supplemental QAQC points. The supplemental QAQC points were collected to be used in independent accuracy testing. The field crew utilized Real-Time Kinematic (RTK) GPS surveying throughout most of the ground control data collection process. Using RTK GPS techniques, observations were performed on a total of 30 LiDAR control points and 152 ground control quality check points. The survey was conducted using a 1-second epoch rate, in a fixed solution RTK mode, with each observation lasting between 60 to 180 seconds. Each station was occupied twice to insure the necessary horizontal and vertical accuracies were being met for this photogrammetric project. The "Virtual Reference Station" (VRS) concept is based on having a network (spaced at 50-60kms) of GNSS (GPS or GPS/GLONASS) reference stations permanently connected to the control center via the Internet. The networked stations collectively and precisely, model Ionospheric errors for the individual GNSS rover in the network coverage area. The rover interprets and uses the VRS network-correction data as if it is operating with a single physical base station on a very short baseline which increases the RTK performance. Corrections (vectors) are from the closest base, but because the ionospheric error (which is traditionally baseline dependent) is practically negated, the rover's degradation in accuracy due to baseline length starts when the rover is first initialized, that is, at the work site. Thus accuracies are increased and more consistent throughout the working region.

Process Date/Time: 2015-03-17 00:00:00
Source: raw lidar data

Process Step 3

CC ID: 623912
Description:

The first delivery of this dataset (August, 2015) to the NOAA Office for Coastal Management arrived via hard-drive device from Woolpert, the contracting the company for this project. An internal review from the CGSC data team at NOAA OCM generated a report with data concerns and alterations required before accepting the data as final. A second delivery arrived in October, 2015 and the dataset was marked as final and accepted for distribution on the Digital Coast. The lidar data were projected to State Plane Georgia West (1002, units in feet) and vertically to NAVD88 heights (feet). OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The data were converted from State Plane (ft) horizontal coordinates to geographic coordinates (decimal degrees) and vertical heights were converted from orthometric (NAVD88, ft) heights to ellipsoidal heights using Geoid12a (m).

2. Erroneous points were removed and LAS files were compressed for data storage. Class 7 (low noise) contained a number of unrealistic elevations and equated to a large percentage of the project files (0.05%), therefore these were removed altogether to prevent processing errors and to save disk space. This was the advise from USGS as set standards have not specifically pertained to the noise classifications.

3. A third delivery came November 30th, 2015. This included 45 updated files. These were incorporated in place of existing files.

Process Date/Time: 2015-11-30 00:00:00
Process Contact: Office for Coastal Management (OCM)
Source: calibrated lidar data

Catalog Details

Catalog Item ID: 48183
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-14 14:19+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2019-07-02 15:17+0000
Metadata Record Published: 2018-03-13
Owner Org: OCM
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Next Review Date: 2019-03-14