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Short Citation:
OCM Partners, 2023: USGS Atchafalaya 2 LiDAR,

Item Identification

Title: USGS Atchafalaya 2 LiDAR
Short Name: la2013_usgs_atchafalaya_m4747_metadata
Status: Completed
Publication Date: 2015-02

The Light Detection and Ranging (LiDAR) dataset is a survey of the Atchafalaya Basin project area. The entire survey area for Atchafalaya encompasses approximately 1650.5 square miles. The LiDAR point cloud was flown at a nominal post spacing of 1.0 meters for unobscured areas. The LiDAR data and derivative products produced are in compliance with the U.S. Geological Survey National Geospatial Program LIDAR Guidelines and Base Specifications, Version 13-ILMF 2010. The flight lines were acquired by Aerial Cartographics of America, Inc "ACA", which required eight missions between December 18, 2012 - March 01, 2013. Derivative products from the aerial acquisition include: raw point cloud data in LAS v1.2 format, classified point cloud data in LAS v1.2 format, bare earth surface (raster DEM) tiles in 32-bit floating point raster ERDAS .IMG format, breaklines in ESRI Arc Shape format, control points in ESRI Arc Shape format, project report, and FGDC compliant XML metadata.


The purpose of this project was to produce a high resolution LiDAR data set to assist in change detection mapping of the Atchafalaya Basin located in Southern Louisiana.



Supplemental Information:

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

A report for this dataset is available at:


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category

Temporal Keywords

Thesaurus Keyword
Season Winter
Year 2013

Spatial Keywords

Thesaurus Keyword
Country United States
Parishes Iberville and St Martin

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:

Lidar points in LAZ format (Classes 1,2,7,9,10,15)

Entity Attribute Detail Citation:


Distribution Liability:

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

Support Roles

Data Steward

CC ID: 676148
Date Effective From: 2015-02
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


CC ID: 676150
Date Effective From: 2015-02
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Metadata Contact

CC ID: 676151
Date Effective From: 2015-02
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Point of Contact

CC ID: 676149
Date Effective From: 2015-02
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1136334
W° Bound: -92.2550429924
E° Bound: -91.1566907901
N° Bound: 30.8269431712
S° Bound: 29.3595954527

Extent Group 1 / Time Frame 1

CC ID: 1136326
Time Frame Type: Discrete
Start: 2012-12-18

Extent Group 1 / Time Frame 2

CC ID: 1136327
Time Frame Type: Discrete
Start: 2012-12-19

Extent Group 1 / Time Frame 3

CC ID: 1136328
Time Frame Type: Discrete
Start: 2012-12-21

Extent Group 1 / Time Frame 4

CC ID: 1136329
Time Frame Type: Discrete
Start: 2013-01-28

Extent Group 1 / Time Frame 5

CC ID: 1136330
Time Frame Type: Discrete
Start: 2013-02-19

Extent Group 1 / Time Frame 6

CC ID: 1136331
Time Frame Type: Discrete
Start: 2013-02-20

Extent Group 1 / Time Frame 7

CC ID: 1136332
Time Frame Type: Discrete
Start: 2013-03-01

Extent Group 1 / Time Frame 8

CC ID: 1136333
Time Frame Type: Discrete
Start: 2013-03-02

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:;

Data Access Constraints:


Data Use Constraints:

The data depicts the elevations at time of survey and are accurate only for that time. Exercise professional judgement in using this data.

Distribution Information

Distribution 1

CC ID: 741215
Download URL:
File Name: Customized Download

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

Distribution 2

CC ID: 741216
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 741218
URL Type:
Online Resource


CC ID: 741219
URL Type:
Online Resource


CC ID: 741220
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the coverage of the 2012 Atchafalaya Louisiana data collection.

Activity Log

Activity Log 1

CC ID: 676176
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 676175
Activity Date/Time: 2017-11-14

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using '' script. Contact Tyler Christensen (NOS) for details.

Activity Log 3

CC ID: 718331
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 741217
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality


These data are not attributed.

Horizontal Positional Accuracy:

There is not a systematic method of testing when testing horizontal accuracy in LiDAR. However this is tested during calibration of the sensor and is rechecked during the comparing of parallel and perpendicular flight lines. Additionally the horizontal accuracy is checked by collecting building corners during the survey. Lines are then digitized representing the building outline and the differences are measure from each individual survey point to the corner of the building outline. Stats are calculated to ensure horizontal tolerances are met. These measurements resulted in an RMSEr of 0.39 meters and equals a RMSE accuracy of 0.68 meter horizontal accuracy at the 95 % confidence level. Method used was the NSSDA standard for horizontal accuracy assessment.

RMSEr * 1.73 = Horizontal Accuracy at the 95% confidence interval. ; Quantitative Value: 0.39 meters, Test that produced the value: 39 cm RMSE (0.68 meter horizontal accuracy at the 95 % confidence level)

Vertical Positional Accuracy:

The accuracy assessment was performed using the NSSDA standard method to compute the root mean square error (RMSE) based on a comparison of ground control points (GCP) and DEM derived from the LiDAR dataset. Testing was performed prior to gridding of the filtered LiDAR data points and construction of the 32-bit ESRI float grid format bare earth tiles. The RMSEz figure was used to compute the vertical National Standard for Spatial Data Accuracy (NSSDA). A spatial proximity analysis was used to select edited LiDAR data points contiguous to the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error and adequate sample size. Cumulative error results from the errors inherent in the various sources of horizontal measurement. These sources include the airborne GPS, GCPs and the uncertainty of the accuracy of the LiDAR data points. This accuracy is achieved prior to the subsampling that occurs through integration with the inertial measurement unit (IMU) positions that are recorded. It is unclear at this time whether the initial accuracy is maintained. The horizontal accuracy of the GCPs is estimated to be in the range of approximately .03 to .04 meters. Finally, sample size was considered. The specification for the National Standard for Spatial Data Accuracy is a minimum of 20 points to conduct a statistically significant accuracy evaluation which provides a reasonable approximation of a normal distribution. The intent of the NSSDA is to reflect the geographic area of interest and the distribution of error in the data set (Federal Geographic Data Committee, 1998, Geospatial National Standard for Spatial Data Accuracy, Federal Geographic Data Committee Secretariat, Reston, Virginia, p.3-4). Additional steps were taken to ensure the vertical accuracy of the LiDAR data including: Step 1: Precision Bore sighting (Check Edge-matching) Step 2: Compare the LiDAR data to the Field Survey (The vertical accuracy requirements meet or exceed the required RMSEz of 12.5cm and the vertical accuracy of 24.5cm at the 95% confidence level). Data collected under this task order exceeds the required National Standards for Spatial Database Accuracy (NSSDA) accuracy standards. SVA accuracies at the 95th Percentile collected and tested, as target accuracies results as follows:Bare-Earth= 0.17, Tall Weeds and Crops=0.24 meters, Brush Lands and Trees= 0.48 , Forested and Fully Grown=0.12 . Consolidated Vertical Accuracies (CVA) at the 95th Percentile =0.32 meters. Final accuracy statement for this task order is as follows; FVA Tested 0.17 meters vertical accuracy at the 95% confidence level.; Quantitative Value: 0.086 meters, Test that produced the value: 8.6 cm RMSEz

Completeness Report:

Ground Truth data was collected of the five major land cover classes present within the study area. 20 points were collected in each of the five vegetation classes that were present within the AOI bare earth, tall weeds and crops, brush lands and trees, forested and fully grown, and swamp and marsh or wetlands. Pair of points was surveyed using the local Gulf-Net RTK Cooperative network once completed the total station is used to collect the taller vegetation classes. A total station was used to collect all the shots collected in the taller vegetation class, due to the limited GPS signal when working in and around vegetation canopy.

Conceptual Consistency:

The GPS survey was tied into the Gulf-Net RTK Cooperative Network located in Louisiana. The Gulf-Net network is a network of continuously operating GPS reference stations that provides Real Time Kinematic (RTK) capabilities within a Real Time Network (RTN). This allows corrections to be applied to the points as they are being collected, eliminating the need for an adjustment. Several existing control monuments listed in the NSRS database were used as checks within the Gulf-Net Network. This confirmed network accuracies were being met during the field survey as well as providing a redundancy check on the Gulf-Net network. The Specified local network accuracy of 5cm at the 95% confidence level was met or exceeded. Data analysis was accomplished by comparing ground truth checkpoints with LIDAR points from the derived DEM and reported three ways 1. FVA 2. SVA 3. CVA. Additionally the FVA points were assessed against the TIN derived from the LAS LiDAR point cloud controlled and calibrated swath data to ensure they met the required accuracy of 12.5cm RMSEz and 24.5cm at the 95% confidence interval.


Process Steps

Process Step 1

CC ID: 1136319

The ABGPS, inertial measurement unit (IMU), and raw scans are collected during the LiDAR aerial survey. The ABGPS monitors the xyz position of the sensor and the IMU monitors the orientation. During the aerial survey, laser pulses reflected from features on the ground surface are detected by the receiver optics and collected by the data logger. GPS locations are based on data collected by receivers on the aircraft and base stations on the ground. The ground base stations are placed no more than 40 km radius from the flight survey area.

Process Date/Time: 2013-03-01 00:00:00

Process Step 2

CC ID: 1136320

The ABGPS, IMU, and raw scans are integrated using proprietary software developed by Lieca and delivered with the Lieca System. The resultant file is in a LAS binary file format. The LAS version 1.2 file format can be easily transferred from one file format to another. It is a binary file format that maintains information specific to the LiDAR data (return number, intensity value, xyz, etc.). The resultant points are produced in the NAD83 UTM 15 North Coordinate System, with units in Meters and referenced to the NAVD88 datum. The LiDAR mass points were processed in American Society for Photogrammetry and Remote Sensing LAS 1.2 format. The header file for each dataset is complete as defined by the LAS 1.2 specification. The datasets were divided into a 1500 meter by 1500 meter tiling scheme, named according to the US National Grid scheme. The tiles are contiguous, do not overlap, and are suitable for seamless topographic data mosaics that include no "no data" areas. The names of the tiles include numeric column and row designations and all files utilize the LAS file extension

Process Date/Time: 2013-03-11 00:00:00

Process Step 3

CC ID: 1136321

The unedited data are classified to facilitate the application of the appropriate feature extraction filters. A combination of proprietary filters are applied as appropriate for the production of bare earth digital elevation models (DEMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature extraction filters are used to produce elevation height surfaces.

Process Date/Time: 2013-04-09 00:00:00

Process Step 4

CC ID: 1136322

Filtered and edited data are subjected to rigorous QA/QC, according to the Northrop Grumman, Advanced GEOINT Solutions Operating Unit Quality Control Plan and Procedures. A series of quantitative and visual procedures are employed to validate the accuracy and consistency of the filtered and edited data. Ground control is established by Northrop Grumman, Advanced GEOINT Solutions Operating Unit and GPS-derived ground control points (GCPs) in various areas of dominant and prescribed land cover. These points are coded according to land cover, surface material, and ground control suitability. A suitable number of points are selected for calculation of a statistically significant accuracy assessment, as per the requirements of the National Standard for Spatial Data Accuracy. A spatial proximity analysis is used to select edited LiDAR data points within a specified distance of the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error, and adequate sample size. Accuracy validation and evaluation is accomplished using proprietary software to apply relevant statistical routines for calculation of Root Mean Square Error (RMSE) and the National Standard for Spatial Data Accuracy (NSSDA), according to Federal Geographic Data Committee (FGDC) specifications.

Process Date/Time: 2013-07-05 00:00:00

Process Step 5

CC ID: 1136323

The Bare Earth DEM was extracted from the raw LIDAR products and attributed with the bare earth elevation for each cell of the DEM. Bare Earth DEMs do not include buildings, vegetation, bridges or overpass structures in the bare earth model. Where abutments were clearly delineated, this transition occurred at the junction of the bridge and abutment. Where this junction was not clear, the extractor used their best estimate to delineate the separation of ground from elevated bridge surface. In the case of bridges over water bodies, if the abutment was not visible, the junction was biased to the prevailing stream bank so as not to impede the flow of water in a hydrographic model. Bare earth surface includes the top of water bodies not underwater terrain, if visible.

Process Date/Time: 2013-07-19 00:00:00

Process Step 6

CC ID: 1136324

The NOAA Office for Coastal Management (OCM) received the topographic lidar files in LAS format from SWFWMD. The files contained lidar easting, northing, elevation, intensity, return number, etc. The data was received in Florida State Plane West 0902 (US ft) and NAVD88 (US ft). OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The files were reviewed and erroneous elevations were removed.

2. Class 11 (withheld) points were reclassed to Class 15 (as needed).

Process Date/Time: 2015-01-15 00:00:00

Catalog Details

Catalog Item ID: 49765
GUID: gov.noaa.nmfs.inport:49765
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:22+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2022-03-16
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16