2019 NOAA NGS Topobathy Lidar DEM: U.S. Virgin Islands
Data Set (DS) | National Geodetic Survey (NGS)GUID: gov.noaa.nmfs.inport:65632 | Updated: January 10, 2024 | Published / External
Summary
Short Citation
National Geodetic Survey, 2024: 2019 NOAA NGS Topobathy Lidar DEM: U.S. Virgin Islands, https://www.fisheries.noaa.gov/inport/item/65632.
Full Citation Examples
These data were collected by Leading Edge Geomatics using a Riegl VQ-880-G II sensor. The data acqusition began January 20, 2019 through June 2, 2019. The data includes topobathy data in LAS 1.4 format classified as created, never classified (0); unclassified (1); ground (2); noise (7); bathymetric bottom (40); water surface (41); derived water surface (42); submerged object, not otherwise specified (e.g., wreck, rock, submerged piling) (43); International Hydrographic Organization S-57 object, not otherwise specified (44); no bottom found (bathymetric lidar point for which no detectable bottom return was received) (45); bathymetic bottom temporal changes (46) in accordance with project specifications.
Distribution Information
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Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.
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GeoTIFF
Bulk download of data files in the original coordinate system
None
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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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
BATHYMETRY, BEACHES, COASTAL BATHYMETRY, COASTAL ELEVATION, DIGITAL ELEVATION/TERRAIN MODEL (DEM), elevation, LAND SURFACE, LIDAR, TERRAIN ELEVATION, TOPOGRAPHY
Child Items
No Child Items for this record.
Contact Information
Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov
Extents
-65.16° W,
-64.534435° E,
18.528116° N,
17.626749° S
Data only covers coastal area.
2019-01-20 - 2019-06-02
Item Identification
Title: | 2019 NOAA NGS Topobathy Lidar DEM: U.S. Virgin Islands |
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Status: | Completed |
Publication Date: | 2021 |
Abstract: |
These data were collected by Leading Edge Geomatics using a Riegl VQ-880-G II sensor. The data acqusition began January 20, 2019 through June 2, 2019. The data includes topobathy data in LAS 1.4 format classified as created, never classified (0); unclassified (1); ground (2); noise (7); bathymetric bottom (40); water surface (41); derived water surface (42); submerged object, not otherwise specified (e.g., wreck, rock, submerged piling) (43); International Hydrographic Organization S-57 object, not otherwise specified (44); no bottom found (bathymetric lidar point for which no detectable bottom return was received) (45); bathymetic bottom temporal changes (46) in accordance with project specifications. |
Purpose: |
The US Virgin Islands have been identified as having cirtical topographic and bathymetric data gaps by NOAA. This lidar data will fill those critical gaps. |
Supplemental Information: |
The full workflow used for this project is found in the final project report submitted to NOAA. |
Keywords
Theme Keywords
Thesaurus | Keyword |
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Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE
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Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM)
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > BATHYMETRY
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > BATHYMETRY > COASTAL BATHYMETRY
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > BEACHES
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > SPECTRAL/ENGINEERING > LIDAR
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ISO 19115 Topic Category |
elevation
|
Spatial Keywords
Thesaurus | Keyword |
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Global Change Master Directory (GCMD) Location Keywords |
OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > VIRGIN ISLANDS
|
Platform Keywords
Thesaurus | Keyword |
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Global Change Master Directory (GCMD) Platform Keywords |
Airplane > Airplane
|
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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Data Set Type: | Elevation |
Maintenance Frequency: | None Planned |
Data Presentation Form: | Model (digital) |
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 |
Data Set Credit: | National Oceanic and Atmospheric Administration (NOAA), National Geodetic Survey (NGS), Remote Sensing Division (RSD), Coastal Mapping Program (CMP) |
Support Roles
Data Steward
Date Effective From: | 2021 |
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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: | 2021 |
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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 |
Metadata Contact
Date Effective From: | 2021 |
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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 |
Originator
Date Effective From: | 2021 |
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Date Effective To: | |
Contact (Organization): | National Geodetic Survey (NGS) |
Address: |
1315 East-West Hwy Silver Spring, MD 20910 |
URL: | https://geodesy.noaa.gov/ |
Extents
Currentness Reference: | Ground Condition |
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Extent Group 1
Extent Group 1 / Geographic Area 1
W° Bound: | -65.16 | |
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E° Bound: | -64.534435 | |
N° Bound: | 18.528116 | |
S° Bound: | 17.626749 | |
Description |
Data only covers coastal area. |
Extent Group 1 / Time Frame 1
Time Frame Type: | Range |
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Start: | 2019-01-20 |
End: | 2019-06-02 |
Spatial Information
Spatial Representation
Representations Used
Grid: | No |
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Vector: | Yes |
Text / Table: | No |
TIN: | No |
Stereo Model: | No |
Video: | No |
Reference Systems
Reference System 1
Coordinate Reference System |
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Access Information
Security Class: | Unclassified |
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Data Access Procedure: |
Data is available online for bulk or custom downloads |
Data Access Constraints: |
None |
Data Use Constraints: |
Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. |
Distribution Information
Distribution 1
Start Date: | 2021-05 |
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End Date: | Present |
Download URL: | https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9414 |
Distributor: | NOAA Office for Coastal Management (NOAA/OCM) (2021 - Present) |
File Name: | Customized Download |
Description: |
Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options. |
File Type (Deprecated): | Zip |
Compression: | Zip |
Distribution 2
Start Date: | 2020-05 |
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End Date: | Present |
Download URL: | https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/NGS_USVI_Topobathy_DEM_2019_9414/ |
Distributor: | NOAA Office for Coastal Management (NOAA/OCM) (2021 - Present) |
File Name: | Bulk Download |
Description: |
Bulk download of data files in the original coordinate system |
File Type (Deprecated): | GeoTIFF |
Distribution Format: | GeoTIFF |
URLs
URL 1
URL: | https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9413/supplemental/extent_ngs_vi_topobathy_m9413.kmz |
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Name: | Browse graphic |
URL Type: |
Browse Graphic
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File Resource Format: | KML |
Description: |
This graphic displays the footprint for this lidar data set. |
URL 2
URL: | https://coast.noaa.gov/dataviewer/ |
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Name: | NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV) |
URL Type: |
Online Resource
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File Resource Format: | HTML |
Description: |
The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer. |
URL 3
URL: | https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9413/supplemental/PR1801_VI1801_TB_C_Topobathy_Lidar_Project_Report_Final.pdf |
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Name: | Project Report |
URL Type: |
Online Resource
|
File Resource Format: | |
Description: |
Topobathymetric Lidar Data Report |
Technical Environment
Description: |
OS Independent |
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Data Quality
Horizontal Positional Accuracy: |
The DEMs are derived from the source lidar and inherit the accuracy of the source data. The DEMs are created using controlled and tested methods to limit the amount of error introduced during DEM production. Lidar vendors calibrate their lidar systems during installation of the system and then again for every project acquired. Typical calibrations include cross flights that capture features from multiple directions that allow adjustments to be performed so that the captured features are consistent between all swaths and cross flights from all directions. This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 41 cm RMSEx/RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 1 meter at a 95% confidence level. Thirty-one checkpoints were photo-identifiable. Using this small sample set of photo-identifiable checkpoints, positional accuracy of this dataset was found to be RMSEx = 31.1 cm and RMSEy = 25.4 cm which equates to ACCURACYr = 69.6 cm at 95% confidence level. The results of the small sample set of checkpoints are within the produced to meet horizontal accuracy criteria. |
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Vertical Positional Accuracy: |
The DEMs are derived from the source lidar and inherit the accuracy of the source data. The DEMs are created using controlled and tested methods to limit the amount of error introduced during DEM production so that any differences identified between the source lidar and final DEMs can be attributed to interpolation differences. DEMs are created by averaging several lidar points within each pixel which may result in slightly different elevation values at a given location when compared to the source LAS, which does not average several lidar points together but may interpolate (linearly) between two or three points to derive an elevation value. The vertical accuracy of the final topobathymetric DEMs was tested by Dewberry with 259 independent checkpoints. The same checkpoints that were used to test the source lidar data were used to validate the vertical accuracy of the final DEM products. The survey checkpoints are evenly distributed throughout the project area and are located in areas of non-vegetated terrain, including bare earth, open terrain, and urban terrain (131); vegetated terrain, including forest, brush, tall weeds, crops, and high grass (94); and submerged bottom areas (34). The vertical accuracy is tested by extracting the elevation of the pixel that contains the x/y coordinates of the checkpoint and comparing these DEM elevations to the surveyed elevations. All checkpoints located in non-vegetated terrain were used to compute the Non-vegetated Vertical Accuracy (NVA). Project specifications require a NVA of 0.196 at the 95% confidence level based on RMSEz (0.10) x 1.9600. All checkpoints located in vegetated terrain were used to compute the Vegetated Vertical Accuracy (VVA). Project specifications require a VVA of 0.294 based on the 95th percentile. All checkpoints located in bathymetric areas were used to compute an accuracy for the bathymetric data. Project specifications require the vertical accuracy for bathymetric data to be 0.363 or better at the 95% confidence level based on RMSEz (0.185) x 1.9600. This DEM dataset was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 10 cm RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz = 0.086, equating to +/- 0.168 at 95% confidence level. This DEM dataset was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 10 cm RMSEz Vertical Accuracy Class. Actual VVA accuracy was found to be +/- 23.6 cm at the 95th percentile. The 5% outliers consisted of 5 checkpoints that are larger than the 95th percentile. These checkpoints had a DZ value of 37.3 cm, 42.3 cm, 35.1 cm, 25.9 cm, and 28.6 cm. This DEMdataset was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 18.5 cm RMSEz Vertical Accuracy Class. Actual Bathymetric accuracy was found to be RMSEz = 12.1 cm, equating to +/- 0.236 at the 95% confidence level. |
Completeness Report: |
Data covers the project boundary. |
Conceptual Consistency: |
Not applicable |
Data Management
Have Resources for Management of these Data Been Identified?: | Yes |
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Approximate Percentage of Budget for these Data Devoted to Data Management: | Unknown |
Do these Data Comply with the Data Access Directive?: | Yes |
Actual or Planned Long-Term Data Archive Location: | NCEI-CO |
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?: |
Data is backed up to tape and to cloud storage. |
Lineage
Sources
Acquisition
Contact Role Type: | Originator |
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Contact Type: | Organization |
Contact Name: | Leading Edge Geomatics |
Processing
Contact Role Type: | Originator |
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Contact Type: | Organization |
Contact Name: | Dewberry |
Process Steps
Process Step 1
Description: |
Data for the Puerto Rico and the US Virgin Islands project was acquired by Leading Edge Geomatics using a Riegl VQ-880-G II sensor. All delivered US Virgin Islands lidar data is referenced to: Horizontal Datum-NAD83 (2011) epoch: 2010 Projection-UTM Zone 20 North Horizontal Units-meters Vertical Datum-NAD83 (2011) Vertical Units-meters Both green lidar data and NIR lidar data were acquired. Leading Edge Geomatics acquired, calibrated, and performed refraction correction for the lidar data. |
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Process Date/Time: | 2020-01-22 00:00:00 |
Process Contact: | NGS Communications and Outreach Branch |
Phone (Voice): | (301) 713-3242 |
Email Address: | ngs.infocenter@noaa.gov |
Process Step 2
Description: |
Dewberry received the calibrated green and NIR data and verified complete coverage. Relative accuracy of the green swaths compared to overlapping and adjacent green swaths as well as the relative accuracy of green swaths compared to overlapping and adjacent NIR swaths was verified through the use of Delta-Z (DZ) orthos created in GeoCue software. Intraswath relative accuracy was verified using Quick Terrain Modeler. Profiles of elevated planar features, such as roofs, were used to verify horizontal alignment between overlapping swaths. Dewberry then verified absolute vertical accuracy of the swath data prior to full-scale production. Dewberry used algoritms in TerraScan to create the intial ground/submerged topography surface. Dewberry used rasterized aggregate extents of refracted points to create automated 2-D breaklines with LAStools and ArcGIS. Light travels at different speeds in air versus water and its speed and direction of travel change when it enters the water column. The refraction correction process accounts for this difference by adjusting the depth (distance traveled) and horizontal position (change of angle/direction) of the lidar points acquired within water. These breaklines delineate areas where the refraction correction was applied to the lidar data by Riegl's automated refraction correction software based on the software's detection of water. Where the automated process missed discrete water bodies that did not contain valid bathymetry (submerged topography) data, breaklines were manually drawn and added to a separate feature class to ensure the correct classification of the point cloud. Dewberry used the 2-D refraction extents and additional bathy features to classify the bathymetric bottom and ground points properly in TerraScan. All lidar data was peer-reviewed. Dewberry's QAQC also included creating void polygons for use during review. All necessary edits were applied to the dataset. GeoCue software was used to update LAS header information, including all projection and coordinate reference system information. The final lidar data are in LAS format 1.4 and point data record format 6. The final classificaton scheme is as follows: 0-Created, never classified 1-Unclassified 2-Ground 7-Noise 40-Bathymetric bottom 41-Water surface 42-Derived water surface 43-Submerged object, not otherwise specified 44-International Hydrograpic Organization (IHO) S-57 objects 45-No bottom found (bathymetric lidar point for which no detectable bottom return was received) 46-Bathymetric bottom temporal changes All data was then verified by an Independent QC department within Dewberry. The independent QC was performed by separate analysts who did not perform manual classification or editing. The independent QC involved quantitative and qualitative reviews. |
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Process Date/Time: | 2021-01-22 00:00:00 |
Process Step 3
Description: |
Lidar data classified as ground (2) and submerged topography (40) were converted to Esri multipoint format. These multipoints were then used to generate a terrain and the terrain was converted to a raster in IMG format with 1 meter pixel resolution. The terrain and output raster were created over the full project area to reduce edge-matching issues and improve seamlessness. The raster was clipped to the tile grid and named according to project specifications to result in tiled topobathymetric DEMs. All tiled DEMs incorporate the use of the void polygons. The void polygons represent bathymetric areas with no bathymetric bottom returns and are set as NoData in the DEMs. Void polygon creation is described in the final project report and the void polygon metadata. A point density layer has been created and provided to NOAA as part of the deliverables. The point density layer is a raster product in IMG format with 1 meter square pixels. The density grid identifies the number of ground and/or bathy bottom points located within each pixel. The pixels in the point density layer align with the pixels in the topobathy DEMs so that the point density layer shows the density of ground/submerged topography points located in each cell that were used to determine elevations for each cell in the topobathy DEMs. Higher density lends itself to higher confidence. The point density layer can be displayed by unique values or classified into desired bins/ranges for analysis over larger areas. A confidence layer has been created and provided to NOAA as part of the deliverables. The confidence layer is a raster product in IMG format with 1 meter square pixels. The confidence layer provides a standard deviation value for every pixel by calculating the standard deviation of all ground and/or submerged topography lidar points that are located within a single pixel. The confidence layer pixels align to the pixels in the topobathy DEMs. The confidence layer can be displayed by unique values or classified into desired bins/ranges for analysis over larger areas. |
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Process Date/Time: | 2020-02-03 00:00:00 |
Process Step 4
Description: |
The NOAA Office for Coastal Management (OCM) received files in IMG format. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. Converted from IMG to TIFF |
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Process Date/Time: | 2021-10-08 00:00:00 |
Process Contact: | Office for Coastal Management (OCM) |
Catalog Details
Catalog Item ID: | 65632 |
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GUID: | gov.noaa.nmfs.inport:65632 |
Metadata Record Created By: | Maryellen Sault |
Metadata Record Created: | 2021-10-21 12:52+0000 |
Metadata Record Last Modified By: | Kirk Waters |
Metadata Record Last Modified: | 2024-01-10 19:20+0000 |
Metadata Record Published: | 2024-01-10 |
Owner Org: | NGS |
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 |