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OCM Partners, 2023: 2001 USGS/NASA Airborne Topographic Mapper (ATM) Lidar: Coastal Alabama, Florida, Louisiana, Mississippi, Texas,

Item Identification

Title: 2001 USGS/NASA Airborne Topographic Mapper (ATM) Lidar: Coastal Alabama, Florida, Louisiana, Mississippi, Texas
Short Name: usgs2001_m525_metadata
Status: Completed
Publication Date: 2009

This is a non-bare earth data set. ASCII xyz point cloud data were produced from remotely sensed, geographically referenced elevation

measurements cooperatively by the U.S. Geological Survey (USGS) and National Aeronautics and Space Administration (NASA) along the coasts

of Alabama, Florida (Panhandle), Louisiana, Mississippi and Texas in 2001.

Dates of collection are:

1. Alabama 20011002-20011004, 20011007-20011010

2. Florida 20011002

3. Louisiana 20010909-20010910

4. Mississippi 20010909-20010910

5. Texas 20011012-20011013

Elevation measurements were collected over the area using the NASA Airborne Topographic Mapper (ATM), a scanning Lidar system that measures

high-resolution topography of the land surface. The ATM system is deployed on a Twin-Otter or P-3 Orion aircraft and incorporates a

green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser ranging device are coupled with data

acquired from internal navigation system (INS) attitude sensors and differentially-corrected global positioning system (GPS) receivers to

measure topography of the surface at accuracies of 10 to 20 centimeters.

Original contact information:

Contact Name: Amar Nayegandhi

Contact Org: Jacobs Technology, U.S. Geological Survey, FISC

Title: Computer Scientist

Phone: 727-803-8747 (x3026)



The ASCII elevation data can be used to create raster Digital Elevation Models (DEMs). The purpose of this project is to produce

highly detailed and accurate elevation maps of the Alabama, Florida (Panhandle), Louisiana, Mississippi, and Texas coastlines for natural

resource managers and research scientists.



Supplemental Information:

Raw Lidar data are not in a format that is generally usable by resource managers and scientists. Converting dense Lidar elevation data

into a readily usable format without loss of essential information requires specialized processing. The U.S. Geological Survey's Coastal

and Marine Geology (CMG) Program has developed custom software to convert raw Lidar data into a GIS-compatible map product to be provided

to GIS specialists, managers, and scientists. The primary tool used in the conversion process is Advanced Lidar Processing System (ALPS),

a multi-tiered processing system developed by a USGS-NASA collaborative project. Specialized processing algorithms are used to convert raw

waveform Lidar data acquired by the EAARL to georeferenced spot (x, y, z) returns for "first surface" and "bare earth" topography. These

data are then converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the GEOID03 model).

The files are in the Quarter-Quad tiling format and the exact tile location is contained in the filename at ########_fs, where ####### is the

Quarter-Quad tile ID.

The development of custom software for creating these data products has been supported by the USGS CMG Program's Decision Support for

Coastal Parks, Sanctuaries, and Preserves project. Processed data products are used by the USGS CMG Program's National Assessments of

Coastal Change Hazards project to quantify the vulnerability of shorelines to coastal change hazards such as severe storms, sea-level rise,

and shoreline erosion and retreat.


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
None ATM

Stratum Keywords

Thesaurus Keyword
None First Surface

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: None Planned
Entity Attribute Overview:

Binary lidar data file for xyz data points.

Entity Attribute Detail Citation:

The variables measured by the ATM are distance between aircraft and GPS satellites (m), attitude information (roll, pitch,

heading in degrees), scan angle (degrees), second of the epoch (sec), and 1ns time-resolved return intensity waveform (digital counts).

Z value is referenced to orthometric elevations derived from National Geodetic Survey Geoid Model, GEOID03.

Distribution Liability:

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

This data was prepared by an agency of the United States Government. Although these data have been processed successfully on a

computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any

other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or

incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by

trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the

United States Government or any agency thereof.

Data Set Credit: Acknowledgment of the U.S. Geological Survey, Florida Integrated Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices for data source is expected. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. The U.S. Geological Survey and National Aeronautics and Space Administration request to be acknowledged as originators of the dataset in future products or derivative research. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photo interpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.

Support Roles

Data Steward

CC ID: 690363
Date Effective From: 2009
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: 690365
Date Effective From: 2009
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: 690366
Date Effective From: 2009
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: 690364
Date Effective From: 2009
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: 1138611
W° Bound: -97.141632
E° Bound: -84.333334
N° Bound: 30.402837
S° Bound: 27.716485

Extent Group 1 / Time Frame 1

CC ID: 1138610
Time Frame Type: Range
Start: 2001-09-09
End: 2001-10-13

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Security Classification System:


Security Handling Description:


Data Access Procedure:

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

Data Access Constraints:


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: 743017
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: 743018
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 743020
URL Type:
Online Resource


CC ID: 743021
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 690390
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 690389
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: 718702
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 743019
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Technical Environment


Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcMap

Data Quality


The expected accuracy of the measured variables is as follows: attitude within 0.07 degree, 3 cm nominal laser ranging accuracy, and vertical

elevation accuracy of +/-15 cm for the topographic surface. Quality checks are built into the data-processing software.

Horizontal Positional Accuracy:

Raw elevation measurements have been determined to be within 1-meter horizontal accuracy.

Vertical Positional Accuracy:

Elevations of the DEM are vertically consistent with the point elevation data, +/-15 cm.

Completeness Report:

Several regions of the dataset are labeled as "No Data". These "No Data" areas are a result of the survey not covering a particular region,

optical water depth of greater than 1.5 Secchi disc depths, or the manual removal of Lidar processing artifacts.

Conceptual Consistency:

The files are in the Quarter-Quad tiling format and the exact tile location is contained in the file name at ########_fs, where ####### is

the Quarter-Quad tile ID. See DOQQ_naming_convention.doc in the 'extras' directory.


Process Steps

Process Step 1

CC ID: 1138606

The data are collected using a twin-otter aircraft. The NASA Airborne Topographic Mapper (ATM) laser scanner collects the data using

a green raster scanning laser. The data are stored on hard drives and archived at the U.S. Geological Survey, FISC office in St. Petersburg,

FL, and the NASA office at Wallops Flight Facility in Virginia. The navigational data are processed at Wallops Flight Facility. The

navigational and raw data are then downloaded into the Advanced Lidar Processing System (ALPS). Data are converted from units of time

to x, y, z points for elevation. The derived surface data can then be converted into raster data (GeoTIFFs).

Process Date/Time: 2009-08-12 00:00:00

Process Step 2

CC ID: 1138607

Metadata imported into ArcCatalog from XML file.

Process Date/Time: 2009-08-01 00:00:00

Process Step 3

CC ID: 1138608

The NOAA Office for Coastal Management (OCM) received the files in LAS format. The files contained LiDAR intensity and elevation measurements.

OCM performed the following processing on the data to make it available within Digital Coast:

1. The data were converted from UTM Zones 14, 15, 16 coordinates to geographic coordinates.

2. The data were converted from NAVD88 heights to ellipsoid heights using Geoid03.

3. The LAS header fields were sorted by latitude and updated.

Process Date/Time: 2009-12-01 00:00:00

Catalog Details

Catalog Item ID: 50098
GUID: gov.noaa.nmfs.inport:50098
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:24+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