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Summary
Item Identification
Keywords
Physical Location
Data Set Info
Support Roles
Extents
Spatial Info
Access Info
Distribution Info
URLs
Data Quality
Lineage
Related Items
Catalog Details

Summary

Browse Graphic

Short Citation
OCM Partners, 2024: 2017 GA DNR Lidar DEM: Middle Chattahoochee - Walter F Watershed, https://www.fisheries.noaa.gov/inport/item/57266.
Full Citation Examples

Abstract

Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the Lidar project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create a 2 meter (6 feet) hydro-flattened Raster DEM data product consists of processed topographic elevation point data derived from multiple return light detection and ranging (lidar) measurements. The lidar data was planned and acquired at 2 points per square meter for the project boundary identified in the shapefile provided NOAA on January 6th, 2017. The developed lidar derivatives are hydro-flattened DEMs.

Geographic Extent: The Atlantic Group, LLC (Atlantic) has successfully completed lidar acquisition for the Georgia 9 County Lidar area of interest (AOI). Lidar for this AOI was acquired in sixteen (16) flight missions completed between November 25th, 2017 and January 24th, 2018. The project area encompasses 1,550,933 acres, 6,276 square kilometers or 2,440 square miles in Georgia covering the Middle Chattahoochee Walter‐F Watershed including Taylor, Chattahoochee, Stewart, Webster, Quitman, Randolph, and Clay Counties; Upper Flint Watershed including portions of Pike, Lamer and Upson Counties; and a portion of Lee County in the Kinchafoonee‐Muckalee Watershed.

In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from, and the hydro breaklines are also available. These data are available for download at the links provided in the URL section of this metadata record.

Distribution Information

  • Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

  • GeoTIFF

    Bulk download of data files in the original coordinate system.

Access Constraints:

None

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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.

Controlled Theme Keywords

elevation, TERRAIN ELEVATION

Child Items

No Child Items for this record.

Contact Information

Point of Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202

Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202

Extents

Geographic Area 1

-85.142949° W, -84.000872° E, 33.190413° N, 31.484983° S

Time Frame 1
2017-11-25 - 2018-01-24

Item Identification

Title: 2017 GA DNR Lidar DEM: Middle Chattahoochee - Walter F Watershed
Short Name: ga2017_chattahoochee_dem_m8840
Status: Completed
Creation Date: 2019-09-11
Abstract:

Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the Lidar project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create a 2 meter (6 feet) hydro-flattened Raster DEM data product consists of processed topographic elevation point data derived from multiple return light detection and ranging (lidar) measurements. The lidar data was planned and acquired at 2 points per square meter for the project boundary identified in the shapefile provided NOAA on January 6th, 2017. The developed lidar derivatives are hydro-flattened DEMs.

Geographic Extent: The Atlantic Group, LLC (Atlantic) has successfully completed lidar acquisition for the Georgia 9 County Lidar area of interest (AOI). Lidar for this AOI was acquired in sixteen (16) flight missions completed between November 25th, 2017 and January 24th, 2018. The project area encompasses 1,550,933 acres, 6,276 square kilometers or 2,440 square miles in Georgia covering the Middle Chattahoochee Walter‐F Watershed including Taylor, Chattahoochee, Stewart, Webster, Quitman, Randolph, and Clay Counties; Upper Flint Watershed including portions of Pike, Lamer and Upson Counties; and a portion of Lee County in the Kinchafoonee‐Muckalee Watershed.

In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from, and the hydro breaklines are also available. These data are available for download at the links provided in the URL section of this metadata record.

Purpose:

The data produced is intended to support local hydrologists and watershed managers in their decision-making processes.

Supplemental Information:

Raster File Type = TIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 2 meter (6 feet)

Interpolation or Resampling Technique = Bi-linear Interpolation

Required Vertical Accuracy = 24.5 cm nva for base spec 1.2

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
ISO 19115 Topic Category Digital Terrain Model
ISO 19115 Topic Category LAS
ISO 19115 Topic Category LiDAR

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > GEORGIA
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
UNCONTROLLED
None Chattahoochee County
None Clay County
None Kinchafoonee-Muckalee Watershed
None Lamar County
None Lee County
None Middle Chattahoochee Walter-F Watershed
None Pike County
None Quitman County
None Randolph County
None Stewart County
None Taylor County
None Upper Flint Watershed
None Upson County
None Webster County

Instrument Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane
Global Change Master Directory (GCMD) Platform Keywords
DEM > Digital Elevation Model

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Elevation
Maintenance Frequency: As Needed
Data Presentation Form: Model (Digital)
Distribution Liability:

The data represented are the result of data collection and processing per contract specifications and indicates the general existing conditions at the time of data collection. As such, it is only valid for its intended use, content, time, and accuracy specifications. The user is responsible for the results of any application of the data for other than its intended purpose.

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

Data Set Credit: The Atlantic Group, LLC, GA DNR

Support Roles

Data Steward

CC ID: 869544
Date Effective From: 2019
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: 869543
Date Effective From: 2019
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

Metadata Contact

CC ID: 869545
Date Effective From: 2019
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: 869546
Date Effective From: 2019
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: 869549
W° Bound: -85.142949
E° Bound: -84.000872
N° Bound: 33.190413
S° Bound: 31.484983

Extent Group 1 / Time Frame 1

CC ID: 869548
Time Frame Type: Range
Start: 2017-11-25
End: 2018-01-24

Spatial Information

Reference Systems

Reference System 1

CC ID: 871721

Coordinate Reference System

CRS Type: Vertical
EPSG Code: EPSG:5703
EPSG Name: NAVD88 height
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk and custom downloads.

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: 869550
Start Date: 2019-08-22
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8840
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2019 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 869551
Start Date: 2019-08-22
End Date: Present
Download URL: https://coast.noaa.gov/htdata/raster2/elevation/GA_Chattahoochee_DEM_2017_8840
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2019 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system.

File Type (Deprecated): GeoTIFF
Distribution Format: GeoTIFF

URLs

URL 1

CC ID: 869540
URL: https://coast.noaa.gov/
Name: NOAA's Office for Coastal Management (OCM) website
URL Type:
Online Resource
File Resource Format: HTML
Description:

Information on the NOAA Office for Coastal Management (OCM)

URL 2

CC ID: 869541
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML
Description:

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

URL 3

CC ID: 871824
URL: https://coast.noaa.gov/htdata/lidar3_z/geoid12b/data/8839/supplemental/17019_Aerial_Lidar_Report.pdf
Name: Data set report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report

URL 4

CC ID: 871825
URL: https://coast.noaa.gov/htdata/lidar3_z/geoid12b/data/8839/breaklines/
URL Type:
Online Resource
Description:

Link to the hydro breaklines.

URL 5

CC ID: 871826
URL: https://coast.noaa.gov/htdata/lidar3_z/geoid12b/data/8839/supplemental/ga2017_chattahoochee_m8839.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

URL 6

CC ID: 871827
URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8839
URL Type:
Online Resource
Description:

Link to custom download the lidar point data from which these raster Digital Elevation Model (DEM) data were created.

Data Quality

Horizontal Positional Accuracy:

As described in Section 7.5 of the ASPRS Positional Accuracy Standards for Digital Geospatial Data the horizontal errors in lidar data are largely a function of GNSS positional error, INS angular error, and flying altitude. Therefore, lidar data collected with GNSS error of 8cm and the IMU error of 0.00427 degrees at an altitude of 1,957m; the expected radial horizontal positional error will be RMSEr = 43cm.

Vertical Positional Accuracy:

Atlantic established a total of fifty -two (52) check points for this project (29 NVA + 23 VVA). Point cloud data accuracy was tested against a Triangulated Irregular Network (TIN) constructed from lidar points in clear and open areas. A clear and open area can be characterized with respect to topographic and ground cover variation such that a minimum of 5 times the NPS exists with less than 1/3 of the RMSEZ deviation from a low-slope plane. Slopes that exceed 10 percent were avoided. Each land cover type representing 10 percent or more of the total project area were tested and reported with a VVA. In land cover categories other than dense urban areas, the tested points did not have obstructions 45 degrees above the horizon to ensure a sufficient TIN surface. The VVA value is provided as a target. It is understood that in areas of dense vegetation, swamps, or extremely difficult terrain, this value may be exceeded. The NVA value is a requirement that must be met, regardless of any allowed “busts” in the VVA(s) for individual land cover types within the project. Checkpoints for each assessment (NVA and VVA) are required to be well-distributed throughout the land cover type, for the entire project area.

Below are the vertical accuracy reporting requirements for this project: Vertical Accuracy Reporting Requirements in Feet:

RMSEZ ≤ 0.328 ft (Non-Vegetated Swath, DEM)

NVA ≤ 0.643 ft 95% Confidence Level (Swath, DEM)

VVA ≤ 0.965 ft 95th Percentile (DEM)

Tested 0.061 meters NVA at a 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA). The NVA of the Point Cloud was calculated using 29 independent checkpoints located in the Bare Earth and Urban land cover categories. The NVA of the Bare Earth was calculated using 67 independent checkpoints located in the Bare Earth and Urban land cover categories.

Tested 0.143 meters VVA was calculated using 53 checkpoints located in the Brushlands and Low Trees and Tall Weeds and Crops land cover categories at the 95th percentile, derived according to ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data. Tested against the DEM.

Tested 0.060 meters NVA at a 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA). The NVA of the DEM was calculated using 67 independent checkpoints located in the Bare Earth and Urban land cover categories.

Completeness Report:

Area of interest covers approximately 2,440 square miles around project area. The raw LAS data files included 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 NVA specifications. Void areas (i.e., areas outside the project boundary but within the tiling scheme) are coded using a unique NODATA value. This value is identified in the appropriate location within the file header.

Conceptual Consistency:

All lidar data and lidar derived data covers the entire 2,440 square mile area of interest. All lidar point cloud tiles show no edge artifacts or mismatches from tile to tile. Void areas (i.e. areas outside the project boundary but within the tiling scheme) are coded using a unique NODATA value. This value is identified in the appropriate location within the file header. Data cover the entire area specified for this project.

Lineage

Process Steps

Process Step 1

CC ID: 869532
Description:

Survey Data Acqisition:

Project Introduction: Platinum Geomatics, LLC entered into contract with the Atlantic Group on March 1st, 2017 to perform geodetic control surveying for the calibration and quality control of 9 counties of LiDAR in South Georgia. This is a report of the methodology used and calculated accuracy of the survey performed by Platinum Geomatics, LLC.

Procedures Used: The Trimble Virtual Reference System (VRS) was employed to obtain real-time GNSS corrections for most of the points. When real-time corrections could not be obtained, due to either poor cellular connection or aerial obstructions affecting the geometric dilution of precision (GDOP), a static GNSS session was run and receiver independent exchange format (RINEX) files of the navigated position were downloaded from the VRS. Static GNSS baselines were post-processed using Trimble Business Center (TBC) software. Real-time VRS observations consisted of a minimum of 180 1-second epochs and point tolerances were set to record within 0.049’ horizontal and 0.066’ vertical accuracies.

Equipment Used: Trimble R-7, R-8, and R-10 dual frequency GNSS receivers were used.

Project Datum: Individual point coordinates were reported to NAD83 (2011) Georgia West zone. Coordinates and elevations were reported in US Survey Feet. Reported Elevations are relative to NAVD88 as derived from Geoid 12B.

Point Description Quantity Non-vegetated LiDAR Quality Control 50, Vegetated LiDAR Quality Control 37, and LiDAR Calibration 26

Process Date/Time: 2017-10-27 00:00:00

Process Step 2

CC ID: 869533
Description:

Flight Acquisition: Atlantic acquired one hundred eighty-one (181) passes of the AOI as a series of perpendicular and/or adjacent flight-lines. Differential GNSS unit in aircraft recorded sample positions at 2 Hz or more frequency. Lidar data was only acquired when a minimum of 6 satellites were in view. Atlantic lidar sensors are calibrated at a designated site located at the Fayetteville Municipal Airport (FYM) in Fayetteville, TN and are periodically checked and adjusted to minimize corrections at project sites. Atlantic operated a Cessna 210TL (N732JE) and Partenavia P68 (N775MW) outfitted with a Leica ALS70-HP lidar system during the collection of the project area. Data acquisition was completed between 24th November 2017 and 24th January 2018.

Process Date/Time: 2017-11-25 00:00:00

Process Step 3

CC ID: 869534
Description:

Lidar Pre-processing: Atlantic used a combination of Waypoint and Leica software products to extract the lidar swath data from the raw flight records. Waypoint Inertial Explorer is used to extract the raw IPAS ABGPS/IMU data, which is further processed in combination with controlled base stations to provide the final Smoothed Best Estimate Trajectory (SBET) for each mission. The SBET’s are combined with the raw laser scan files to export the (*.las) formatted swath point clouds.

Process Date/Time: 2019-07-02 00:00:00

Process Step 4

CC ID: 869535
Description:

LiDAR ranging data were initially calibrated using previous best parameters for this instrument and aircraft. Using a combination of GeoCue, and TerraSolid’s TerraScan and TerraMatch the overlapping swath point clouds are corrected for any orientation or linear deviations to obtain the best fit swath-to-swath calibration. Relative calibration was evaluated using advanced plane-matching analysis and parameter corrections derived. This process was repeated interactively until residual errors between overlapping swaths, across all project missions, was reduced to 2 cm or less. A final analysis of the calibrated LiDAR is preformed using a TerraMatch Tie Line report for an overall statistical model of the project area.

Upon completion of the data calibration, Atlantic runs a complete set of Delta-Z (dZ) ortho images. A user-defined color ramp is applied depicting the offsets between overlapping swaths based on project specifications. The dZ orthos provide an opportunity to review the data calibration in a qualitative manner. Atlantic assigns green to all offset values that fall below the required interswath accuracy RMSDz requirement of the project. A yellow color is assigned for offsets that fall between the RMSDz value and 1.5x of that value. Finally, red values are assigned to all values that fall beyond 1.5x of the RMSDz requirements of the project.

The calibrated point cloud data from the laser sensor was merged to produce processed (*.las) file(s) including but not limited to 3D position, intensity, and time-stamp. A filtering methodology was utilized to produce a multi-return surface elevation model dataset with bare-earth conditions. GeoCue, TerraScan, and TerraModel software was used for the initial batch processing and manual editing of the (*.las) point clouds. Atlantic utilized collected breakline data to perform classification for classes’ 9-Water and 10-Ignored Ground in LP360.

Process Date/Time: 2019-07-02 00:00:00

Process Step 5

CC ID: 869536
Description:

Lidar Intensity Imagery Creation: All lidar intensity imagery was created from the final calibrated and classified lidar point cloud. Intensity images were produced from all classified points.

Process Date/Time: 2019-07-02 00:00:00

Process Step 6

CC ID: 869537
Description:

Hydro line Collection: Hydro lines were compiled as water bodies (ponds and lakes) 2 acres or greater, and streams and rivers (“double-line”) 100 nominal feet wide or greater, using the lidar intensity data and surface terrain model of the entire project area. After the collection of hydro lines all features were validated for monotonicity and vertical variance, to ensure that no points were floating above ground. The hydro break lines were encoded into the lidar surface and used to hydro-enforce/flatten all significant water bodies. These final hydro lines were then used in the production of bare Earth digital models to hydro flatten significant water bodies.

Process Date/Time: 2019-07-02 00:00:00

Process Step 7

CC ID: 869538
Description:

Bare-Earth Hydro-flattened DEMs were created in LP-360 from the hydro lines and bare-earth (ground) LiDAR data. All DEMs were created with a cell size of 6 feet. Delivery in an industry-standard, GIS-compatible, 32-bit ERDAS GeoTIFF raster format and cut to the project index tiles. Each surface is reviewed using Global Mapper to check for any surface anomalies or incorrect elevations found within the surface.

Process Date/Time: 2019-07-19 00:00:00

Process Step 8

CC ID: 869584
Description:

The NOAA Office for Coastal Management (OCM) received 3052 raster DEM files in GeoTiff format from Tetra Tech. The data were in GA State Plane West, NAD83(2011), US Survey feet, coordinates and NAVD88 (Geoid12b) elevations in meters. The bare earth raster files were at a 6 ft grid spacing.

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

1. Used internal script to assign the EPSG codes.

2. Copied to the files to https.

Process Date/Time: 2019-08-22 00:00:00
Process Contact: Office for Coastal Management (OCM)

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2017 GA DNR Lidar: Middle Chattahoochee - Walter F Watershed

Catalog Details

Catalog Item ID: 57266
GUID: gov.noaa.nmfs.inport:57266
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2019-08-22 16:06+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-10-17 16:12+0000
Metadata Record Published: 2019-09-11
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2019-09-11
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2020-09-11