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Summary

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Short Citation
Office for Coastal Management, 2024: 2011 NOAA Bathymetric Lidar: U.S. Virgin Islands - St. Thomas, St. John, St. Croix (Salt River Bay, Buck Island), https://www.fisheries.noaa.gov/inport/item/48218.
Full Citation Examples

Abstract

This data represents a LiDAR (Light Detection & Ranging) gridded bathymetric surface and a gridded relative seafloor reflectivity surface (incorporated into the las format as intensity) for an area of shallow seabed:

1. Surrounding St. Thomas and St. John (STT/STJ): 3m x 3m grid

2. Mouth of Salt River Bay (SARI) in St. Croix: 5m x 5m grid

3. Buck Island Reef National Monument (BUIS) in St. Croix: 3m x 3m grid

Fugro LADS, in collaboration with NOAA's National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Branch, the University of New Hampshire and the National Park Service, acquired bathymetry, relative seafloor reflectivity and hyperspectral imagery in St. Thomas and St. John on thirteen separate dates between 1/29/2011 to 2/28/2011 and in St. Croix (SARI and BUIS) on 2/21/2011 and 2/22/2011.

1. STT/STJ

Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 210 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing

and 200% seabed coverage. For STT/STJ, 168.1 square kilometers of LiDAR were collected between 0 m and 40 m in depth. Data was flown for charting. This data met IHO Order 1 standards.

2. SARI

Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 5x5 meter spot spacing

and 200% seabed coverage. For SARI, 1.62 square kilometers of LiDAR were collected between 0 m and 34 m in depth. This data was collected for research, not charting. It was collected using the same acquistion parameters as STT/STJ, but its uncertainties were not quantified. As such, it is not known if this data meets IHO Order 1 standards.

3. BUIS

Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing

and 200% seabed coverage. For BUIS, 35.9 square kilometers of LiDAR were collected between 0 m and 49 m in depth. This data was collected for research, not charting. It was collected using the same acquistion parameters as STT/STJ, but its uncertainties were not quantified. As such, it is not known if this data meets IHO Order 1 standards.

The data received from NCCOS were in GEOTIFF format for both the lidar and seafloor reflectivity. The NOAA Office for Coastal Management converted these two data sets to text format and then combined them into one text file based on x and y. The text file was then converted to las format, where the seafloor reflectivity is represented as intensity. The data's horizontal coordinate system was NAD83 UTM 20 North, and depth values were collected in meters referenced to Mean Lower Low Water (MLLW) depths. Upon receipt of the data, the NOAA Office for Coastal Management converted the data to geographic coordinates and ellipsoid heights

for data storage and Digital Coast provisioning purposes.

Environmental factors such as wind strength and direction, cloud cover, water clarity and depth influenced the area of data acquisition on a daily basis. The data was processed using the LADS Mark II Ground System and data visualization, quality control and final products were created using CARIS HIPS and SIPS and CARIS BASE Editor. All users should individually evaluate the suitability of this data according to their own needs and standards.

Original contact information:

Contact Org:

National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA),

Biogeography Branch

Phone: 301-713-3028

Email: ccma@noaa.gov

Distribution Information

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

  • Simple download of data files.

Access Constraints:

None, but please cite any use of this data.

Use Constraints:

Note: NOT TO BE USED FOR NAVIGATION. These data were prepared by an agency of the United States Government. Neither the United States

Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or

responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report,

or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or

service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or

favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily

state or reflect those of the United States Government or any agency thereof. Although all data have been used by NOAA, no warranty,

expressed or implied, is made by NOAA as to the accuracy of the data and/or related materials. The act of distribution shall not

constitute any such warranty, and no responsibility is assumed by NOAA in the use of these data or related materials.

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

COASTAL ELEVATION, elevation, SEAFLOOR TOPOGRAPHY, TOPOGRAPHICAL RELIEF MAPS

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
https://coast.noaa.gov

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

Extents

Geographic Area 1

-65.07231° W, -64.554218° E, 18.420755° N, 17.763395° S

Time Frame 1
2011-01-29 - 2011-02-28

Item Identification

Title: 2011 NOAA Bathymetric Lidar: U.S. Virgin Islands - St. Thomas, St. John, St. Croix (Salt River Bay, Buck Island)
Short Name: usvi2011_bathy_m1394_metadata
Status: Completed
Publication Date: 2013-06
Abstract:

This data represents a LiDAR (Light Detection & Ranging) gridded bathymetric surface and a gridded relative seafloor reflectivity surface (incorporated into the las format as intensity) for an area of shallow seabed:

1. Surrounding St. Thomas and St. John (STT/STJ): 3m x 3m grid

2. Mouth of Salt River Bay (SARI) in St. Croix: 5m x 5m grid

3. Buck Island Reef National Monument (BUIS) in St. Croix: 3m x 3m grid

Fugro LADS, in collaboration with NOAA's National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Branch, the University of New Hampshire and the National Park Service, acquired bathymetry, relative seafloor reflectivity and hyperspectral imagery in St. Thomas and St. John on thirteen separate dates between 1/29/2011 to 2/28/2011 and in St. Croix (SARI and BUIS) on 2/21/2011 and 2/22/2011.

1. STT/STJ

Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 210 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing

and 200% seabed coverage. For STT/STJ, 168.1 square kilometers of LiDAR were collected between 0 m and 40 m in depth. Data was flown for charting. This data met IHO Order 1 standards.

2. SARI

Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 5x5 meter spot spacing

and 200% seabed coverage. For SARI, 1.62 square kilometers of LiDAR were collected between 0 m and 34 m in depth. This data was collected for research, not charting. It was collected using the same acquistion parameters as STT/STJ, but its uncertainties were not quantified. As such, it is not known if this data meets IHO Order 1 standards.

3. BUIS

Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing

and 200% seabed coverage. For BUIS, 35.9 square kilometers of LiDAR were collected between 0 m and 49 m in depth. This data was collected for research, not charting. It was collected using the same acquistion parameters as STT/STJ, but its uncertainties were not quantified. As such, it is not known if this data meets IHO Order 1 standards.

The data received from NCCOS were in GEOTIFF format for both the lidar and seafloor reflectivity. The NOAA Office for Coastal Management converted these two data sets to text format and then combined them into one text file based on x and y. The text file was then converted to las format, where the seafloor reflectivity is represented as intensity. The data's horizontal coordinate system was NAD83 UTM 20 North, and depth values were collected in meters referenced to Mean Lower Low Water (MLLW) depths. Upon receipt of the data, the NOAA Office for Coastal Management converted the data to geographic coordinates and ellipsoid heights

for data storage and Digital Coast provisioning purposes.

Environmental factors such as wind strength and direction, cloud cover, water clarity and depth influenced the area of data acquisition on a daily basis. The data was processed using the LADS Mark II Ground System and data visualization, quality control and final products were created using CARIS HIPS and SIPS and CARIS BASE Editor. All users should individually evaluate the suitability of this data according to their own needs and standards.

Original contact information:

Contact Org:

National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA),

Biogeography Branch

Phone: 301-713-3028

Email: ccma@noaa.gov

Purpose:

This LiDAR collection is an important effort in an ongoing NOAA scientific research mission in the US Caribbean to characterize nearshore to deep water coral reef habitats at depths down to 1,000 meters. The mission purpose is to better understand the resources within the surveyed reef habitats, and ultimately develop species utilization models linking physical habitats with biological information. The acquired bathymetry, relative seafloor reflectivity, and hyperspectral imagery will be used internally to characterize sea floor topography and to create benthic habitat maps, helping NOAA meet its mapping commitment to the US Coral Reef Task Force. The resulting publicly-distributed data is also a contribution to the greater scientific community interested in the USVI seafloor.

Notes:

10241

Supplemental Information:

The Descriptive Report for the STT/STJ data may be accessed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/supplemental/LiDAR_2011_StThomasJohn_DAPR.pdf

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/supplemental/2011_NOAA_USVI_Bathy_Lidar.kmz

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
UNCONTROLLED
None Backscatter
None Benthic
None Coral
None Depth
None High-resolution
None Integrated Ocean and Coastal Mapping
None Intensity
None IOCM
None LADS Mark II
None NOAA
None NPS
None Reef
None Reef Habitat
None Reflectivity
None Seafloor

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > VIRGIN ISLANDS

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: As Needed
Data Presentation Form: las
Distribution Liability:

These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof,

nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy,

completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would

not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark,

manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States

Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the

United States Government or any agency thereof. Although all data have been used by NOAA, no warranty, expressed or implied, is made by

NOAA as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no

responsibility is assumed by NOAA in the use of these data or related materials. Any conclusions drawn from the analysis of this

information are not the responsibility of the NOAA Office for Coastal Management or its partners.

Data Set Credit: NOAA's NOS/NCCOS/CCMA Biogeography Branch, the University of New Hampshire and the National Park Service

Support Roles

Data Steward

CC ID: 625297
Date Effective From: 2013-06
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: 625299
Date Effective From: 2013-06
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: 625300
Date Effective From: 2013-06
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: 625298
Date Effective From: 2013-06
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: 1133018
W° Bound: -65.07231
E° Bound: -64.554218
N° Bound: 18.420755
S° Bound: 17.763395

Extent Group 1 / Time Frame 1

CC ID: 1133017
Time Frame Type: Range
Start: 2011-01-29
End: 2011-02-28

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=1394

This data set is dynamically generated based on user-specified parameters.

;

Data Access Constraints:

None, but please cite any use of this data.

Data Use Constraints:

Note: NOT TO BE USED FOR NAVIGATION. These data were prepared by an agency of the United States Government. Neither the United States

Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or

responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report,

or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or

service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or

favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily

state or reflect those of the United States Government or any agency thereof. Although all data have been used by NOAA, no warranty,

expressed or implied, is made by NOAA as to the accuracy of the data and/or related materials. The act of distribution shall not

constitute any such warranty, and no responsibility is assumed by NOAA in the use of these data or related materials.

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: 744035
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1394
Distributor:
File Name: Customized Download
Description:

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

Distribution 2

CC ID: 744036
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/index.html
Distributor:
File Name: Bulk Download
Description:

Simple download of data files.

URLs

URL 1

CC ID: 744038
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 744039
URL: https://coast.noaa.gov
URL Type:
Online Resource

URL 3

CC ID: 744040
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/supplemental/2011_NOAA_USVI_Bathy_Lidar.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz
Description:

This graphic shows the lidar coverage for the 2011 NOAA USVI bathymetric lidar.

Activity Log

Activity Log 1

CC ID: 625339
Activity Date/Time: 2016-05-23
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 625338
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: 717989
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 744037
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Technical Environment

Description:

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.4000

Data Quality

Horizontal Positional Accuracy:

The lidar survey for STT/STJ met the IHO Order 1 Standard. The data for SARI and BUIS were collected for research, not charting.

They were collected using the same acquistion parameters as STT/STJ, but their uncertainties were not quantified. As such,

it is not known if this data in these two areas, met IHO Order 1 standards.

Please refer to the Descriptive Report for STT/STJ for additional information:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/supplemental/LiDAR_2011_StThomasJohn_DAPR.pdf

Vertical Positional Accuracy:

The lidar survey for STT/STJ met the IHO 1 Order Standard. The data for SARI and BUIS were collected for research, not charting.

They were collected using the same acquistion parameters as STT/STJ, but their uncertainties were not quantified. As such,

it is not known if the data in these two areas met IHO Order 1 standards.

Please refer to the Descriptive Report for STT/STJ additional information:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/supplemental/LiDAR_2011_StThomasJohn_DAPR.pdf

Completeness Report:

This is a gridded dataset. The original full-resolution Lidar data was used to create a down sampled uniform-resolution surface in CARIS.

Conceptual Consistency:

All users should independently analyze the dataset according to their own needs and standards to determine data usability.

Lineage

Sources

CARIS BASE Surface

CC ID: 1133009
Extent Type: Range
Extent Start Date/Time: 2011-02
Extent End Date/Time: 2011-03
Source Contribution:

Down sampled CARIS BASE (Bathymetry Associated with Statistical Error) grid with best depth layer.

Sourced from processed HDCS data.

| Source Geospatial Form: raster digital data | Type of Source Media: external hard drive

GeoTIFFs of: 1. 3x3 m Bathymetry for St. Thomas & St. John, 2011, UTM 20N NAD83, 3x3 m Relative Reflectivity for St. Thomas & St. John, 2011, UTM 20N NAD83 2. 5x5 m Bathymetry for Salt River Bay, St. Croix, 2011, UTM 20N NAD83, 5x5 m Relative Reflectivity for Salt River Bay, St. Croix, 2011, UTM 20N NAD83 3. 3x3 m Bathymetry for Buck Island, St. Croix, 2011, UTM 20N NAD83, 3x3 m Relative Reflectivity for Buck Island, St. Croix, 2011, UTM 20N NAD83

CC ID: 1133010
Publish Date: 2011-01-01
Extent Type: Range
Extent Start Date/Time: 2011-02
Extent End Date/Time: 2011-03
Source Contribution:

Down sampled GeoTIFF raster containing depth values in meters (referenced to MLLW). Sourced from CARIS BASE surface.

Down sampled GeoTIFF raster containing relative reflectivity (intensity) values. These values do not have units given the complexity of

modeling losses through the water-column and at the water/air interface. Because the dataset is of relative reflectivity rather than

an absolute value for each point, the entire dataset is scaled to ensure the full dynamic range is used over the dataset. This

scaling is applied over an entire survey area to ensure dataset consistency. Sourced from CARIS BASE surface.

| Source Geospatial Form: raster digital data | Type of Source Media: external hard drive

Processed Lidar Data

CC ID: 1133011
Extent Type: Range
Extent Start Date/Time: 2011-02
Extent End Date/Time: 2011-03
Source Contribution:

Processed, cleaned, and corrected full resolution dataset. Sourced from raw LADS data. | Source Geospatial Form: digital data | Type of Source Media: external hard drive

Raw Lidar Data

CC ID: 1133012
Extent Type: Range
Extent Start Date/Time: 2011-01-29
Extent End Date/Time: 2011-02-28
Source Contribution:

Original raw full resolution dataset. | Source Geospatial Form: digital data | Type of Source Media: external hard drive

Process Steps

Process Step 1

CC ID: 1133013
Description:

1. STT/STJ

James Guilford and Scott Ramsay from Fugro LADS led this mapping effort. Hyperspectral data were acquired using a Hyspex VNIR-1600

sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from

altitudes between 1,200 and 2,200ft at ground speeds between 140 and 210 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium

aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing and 200% seabed coverage. Green laser pulses are scanned beneath

the aircraft in a rectilinear pattern. The pulses are reflected from the land, sea surface, within the water column and from the

seabed. The height of the aircraft is determined by the infrared laser return, which is supplemented by the inertial height from the

Attitude and Heading Reference System and GPS height. Real-time positioning is obtained by an Ashtech GG24 GPS receiver combined

with Wide Area DGPS (Differential Global Positioning System) provided by the Fugro Omnistar to provide a differentially corrected

position. Ashtech Z12 GPS receivers are also provided as part of the Airborne System and Ground Systems to log KGPS (Kinetic Global

Positioning System) data on the aircraft and at a locally established GPS (Global Positioning System) base station.

2. SARI

James Guilford and Scott Ramsay from Fugro LADS lead this mapping effort. Hyperspectral data were acquired using a Hyspex VNIR-1600

sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from

altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium

aluminum garnet) laser (1064 nm) acquired 5x5 meter spot spacing and 200% seabed coverage. Green laser pulses are scanned beneath

the aircraft in a rectilinear pattern. The pulses are reflected from the land, sea surface, within the water column and from the

seabed. The height of the aircraft is determined by the infrared laser return, which is supplemented by the inertial height from the

Attitude and Heading Reference System and GPS height. Real-time positioning is obtained by an Ashtech GG24 GPS receiver combined

with Wide Area DGPS (Differential Global Positioning System) provided by the Fugro Omnistar to provide a differentially corrected

position. Ashtech Z12 GPS receivers are also provided as part of the Airborne System and Ground Systems to log KGPS (Kinetic Global

Positioning System) data on the aircraft and at a locally established GPS (Global Positioning System) base station.

3. BUIS

James Guilford and Scott Ramsay from Fugro LADS lead this mapping effort. Hyperspectral data were acquired using a Hyspex VNIR-1600

sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from

altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium

aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing and 200% seabed coverage. Green laser pulses are scanned beneath the

aircraft in a rectilinear pattern. The pulses are reflected from the land, sea surface, within the water column and from the

seabed. The height of the aircraft is determined by the infrared laser return, which is supplemented by the inertial height from the

Attitude and Heading Reference System and GPS height. Real-time positioning is obtained by an Ashtech GG24 GPS receiver combined

with Wide Area DGPS (Differential Global Positioning System) provided by the Fugro Omnistar to provide a differentially corrected

position. Ashtech Z12 GPS receivers are also provided as part of the Airborne System and Ground Systems to log KGPS (Kinetic Global

Positioning System) data on the aircraft and at a locally established GPS (Global Positioning System) base station.

Process Date/Time: 2011-01-01 00:00:00

Process Step 2

CC ID: 1133014
Description:

The reflectivity of an LADS pulse is a measure of the amount of energy reflected from the seabed for each individual laser pulse at the

wavelength of the laser, 532nm (green/blue). The basic difference between processing an ALB waveform for depth and for reflectivity

is that depth processing focuses on the leading edge of the return waveform, whereas reflectivity requires integration of the entire

return pulse. Each sounding is assessed for suitability. Dry soundings and soundings in very shallow water are not processed for

reflectivity. Each sounding is normalized for the electronic gain applied to the photo multiplier tube to which the received laser

energy is optically routed. The gain-normalized return waveform is then analyzed to determine energy returning from the seabed.

Integration of the waveform from the seabed will produce a numerical value of reflectivity. To ensure that this value accurately and

meaningfully describes variation in seabed reflectivity several parameters must be taken into consideration. Energy is lost from the

pulses transmitted from the aircraft. These losses include the air/water interface and those through the water column, and any system

specific losses such as optical filtering and receiver field of view. Reflectivity value, calculated for each pulse, is the ratio between

the received energy normalized for the losses described and the transmitted energy. Once a relative reflectivity value has been calculated,

further statistical cleaning to remove outliers is completed. Because the dataset is of relative reflectivity rather than an absolute

value for each point, the entire dataset is scaled to ensure the full dynamic range is used over the dataset. This scaling is applied

over an entire survey area to ensure dataset consistency (Collins et al. 2007). Collins et al. 2007 is available online here:

http://www.fugrolads.com/datasheets/Hydro_Intl_LiDAR_Seabed_Classification.pdf

Process Date/Time: 2011-01-01 00:00:00

Process Step 3

CC ID: 1133015
Description:

The NOAA Office for Coastal Management received the bathymetric and reflectivity gridded data in GEOTIFF format. The data were in UTM Zone 20N,

NAD83 coordinates and were vertically referenced to MLLW. The vertical units of the data were meters. OCM performed the following

processing for data storage and Digital Coast provisioning purposes:

1. The bathymetric and reflectivity data were converted from GEOTIFF format to text format.

2. A perl script, brundle.pl was created to combine the bathymetric and reflectivity text data sets into one text file based on x and y.

The new text file format was x, y, z, r.

3. The new xyzr text file was processed through VDatum to convert from UTM coordinates to geographic coordinates and to convert

from MLLW depths to ellipsoid heights using Geoid12A.

4. Data were converted from txt to las format and the points given a NOAA OCM bathymetric classification of 11 using the lastools tool,

txt2las. The reflectivity data were incorporated into the las format and are represented as intensity.

5. Data were filtered for outliers using the lastools tool, las2las

6. Data were zipped to laz format

Process Date/Time: 2013-04-01 00:00:00

Catalog Details

Catalog Item ID: 48218
GUID: gov.noaa.nmfs.inport:48218
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-14 14:20+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: OCM
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