2011 NOAA Bathymetric Lidar: U.S. Virgin Islands - St. Thomas, St. John, St. Croix (Salt River Bay, Buck Island)
Data Set (DS) | Office for Coastal Management (OCM)GUID: gov.noaa.nmfs.inport:48218 | Updated: August 9, 2022 | Published / External
Summary
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
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.
None, but please cite any use of this data.
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
-65.07231° W,
-64.554218° E,
18.420755° N,
17.763395° S
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) |
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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 |
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City: | Charleston |
State/Province: | SC |
Data Set Information
Data Set Scope Code: | Data Set |
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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
Date Effective From: | 2013-06 |
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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
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
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
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 |
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Extent Group 1
Extent Group 1 / Geographic Area 1
W° Bound: | -65.07231 | |
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E° Bound: | -64.554218 | |
N° Bound: | 18.420755 | |
S° Bound: | 17.763395 |
Extent Group 1 / Time Frame 1
Time Frame Type: | Range |
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Start: | 2011-01-29 |
End: | 2011-02-28 |
Spatial Information
Spatial Representation
Representations Used
Vector: | Yes |
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Access Information
Security Class: | Unclassified |
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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
Download URL: | https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1394 |
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Distributor: | |
File Name: | Customized Download |
Description: |
Create custom data files by choosing data area, product type, map projection, file format, datum, etc. |
Distribution 2
Download URL: | https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/index.html |
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Distributor: | |
File Name: | Bulk Download |
Description: |
Simple download of data files. |
URLs
URL 1
URL: | https://coast.noaa.gov/dataviewer |
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URL Type: |
Online Resource
|
URL 2
URL: | https://coast.noaa.gov |
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URL Type: |
Online Resource
|
URL 3
URL: | https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1394/supplemental/2011_NOAA_USVI_Bathy_Lidar.kmz |
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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
Activity Date/Time: | 2016-05-23 |
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Description: |
Date that the source FGDC record was last modified. |
Activity Log 2
Activity Date/Time: | 2017-11-14 |
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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
Activity Date/Time: | 2018-02-08 |
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Description: |
Partial upload of Positional Accuracy fields only. |
Activity Log 4
Activity Date/Time: | 2018-03-13 |
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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 |
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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 |
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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
Extent Type: | Range |
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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
Publish Date: | 2011-01-01 |
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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
Extent Type: | Range |
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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
Extent Type: | Range |
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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
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. |
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Process Date/Time: | 2011-01-01 00:00:00 |
Process Step 2
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 |
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Process Date/Time: | 2011-01-01 00:00:00 |
Process Step 3
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 |
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Process Date/Time: | 2013-04-01 00:00:00 |
Catalog Details
Catalog Item ID: | 48218 |
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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 |