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Short Citation:
Office for Coastal Management, 2023: 2015 NOAA NGS Topobathy Lidar DEM: Puerto Rico, https://www.fisheries.noaa.gov/inport/item/48380.

Item Identification

Title: 2015 NOAA NGS Topobathy Lidar DEM: Puerto Rico
Short Name: pr2015_ngs_topobathy_dem_m6211_metadata
Status: Completed
Publication Date: 2017-01-11
Abstract:

These data were collected by the National Oceanic Atmospheric Administration National Geodetic Survey Remote Sensing Division using a Riegl VQ-820G system. The data were acquired from 201410- 201505 in fifty three missions. The data includes topobathy data in an LAS 1.2 format file classified as unclassified (1), ground (2), topo noise (7), water column (25), bathymetric bottom or submerged topography (26), water surface (27), submerged object (29), and International Hydrographic Organization (IHO) S-57 objects (30) in accordance with project specifications. The project consists of 525 square miles along the shores of Puerto Rico. This dataset contains 5721 - 500 m x 500 m lidar tiles.

Original contact information:

Contact Org: National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Geodetic Survey (NGS), Remote Sensing Division

Title: Chief, Remote Sensing Division

Phone: 301-713-2663

Purpose:

This lidar data was required by the National Geodetic Survey (NGS), Remote Sensing Division Coastal Mapping Program (CMP) to enable accurate and consistent measurement of the national shoreline. The CMP works to provide a regularly updated and consistent national shoreline to define America's marine territorial limits and manage coastal resources.

Notes:

11399

Supplemental Information:

Data include all lidar returns. An automated grounding classification algorithm was used to determine bare earth and submerged topography point classification. The automated grounding was followed with manual editing. Classes 2 (ground) and 26 (submerged topography) were used to create the final DEMs. The full workflow used for this project is found in the Puerto Rico Processing and QC documentation.

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 > BATHYMETRY
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
UNCONTROLLED
CoRIS Discovery Thesaurus Geographic Information > lidar
CoRIS Theme Thesaurus EARTH SCIENCE > Land Surface > Topography> Terrain Elevation
CoRIS Theme Thesaurus EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Bathymetry
ISO 19115 Topic Category elevation
NOAA NOS Harvest Catalog CoRIS
None Bathymetry
None Bathymetry/Topography
None lidar
None Topography

Temporal Keywords

Thesaurus Keyword
UNCONTROLLED
None 20141102
None 20141103
None 20141109
None 20141110
None 20141111
None 20141113
None 20141114
None 20141115
None 20141116
None 20150402
None 20150403
None 20150406
None 20150407
None 20150408
None 20150409
None 20150413
None 20150414
None 20150415
None 20150416
None 20150417
None 20150418
None 20150420
None 20150421
None 20150422
None 20150423
None 20150424
None 20150425
None 20150427
None 20150504
None 20150505
None 20150506
None 20150507
None 20150508
None 20150509
None 20150511
None 20150512
None 20150513
None 20150514
None 20150515
None 20150517
None 20150518
None 20150519
None 20150520

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > PUERTO RICO
UNCONTROLLED
CoRIS Place Thesaurus COUNTRY/TERRITORY > United States of America > Puerto Rico > Puerto Rico (18N066W0000)
CoRIS Place Thesaurus OCEAN BASIN > Atlantic Ocean > Caribbean Sea /North Atlantic Ocean > Puerto Rico > Puerto Rico (18N066W0000)
None Puerto Rico
None United States

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
Data Presentation Form: Map (digital)
Distribution Liability:

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

Data Set Credit: We request that you credit the National Oceanic and Atmospheric Administration (NOAA) when you use these data in a report, publication, or presentation.

Support Roles

Data Steward

CC ID: 632472
Date Effective From: 2017-01-11
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: 632474
Date Effective From: 2017-01-11
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: 632475
Date Effective From: 2017-01-11
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: 632473
Date Effective From: 2017-01-11
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: 632478
W° Bound: -67.296377
E° Bound: -65.539127
N° Bound: 18.528369
S° Bound: 17.850323

Extent Group 1 / Time Frame 1

CC ID: 632477
Time Frame Type: Range
Start: 2014-11-02
End: 2015-05-20

Spatial Information

Spatial Representation

Representations Used

Grid: 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=6211;

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

CC ID: 746557
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=6211
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: 746558
Download URL: https://coast.noaa.gov/htdata/raster2/elevation/PR_Puerto_Rico_NGS_DEM_2015_6211
Distributor:
File Name: Bulk Download
Description:

Simple download of data files.

URLs

URL 1

CC ID: 746560
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 746561
URL: https://coast.noaa.gov/dataregistry
URL Type:
Online Resource

URL 3

CC ID: 746562
URL: https://coast.noaa.gov
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 632541
Activity Date/Time: 2017-02-01
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 632540
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: 717955
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 746559
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Technical Environment

Description:

OS Independent

Data Quality

Horizontal Positional Accuracy:

Project specifications require horizontal positions to meet 1.0m RMSE.; Quantitative Value: 1 meters, Test that produced the value: Independent horizontal accuracy testing requires photo-identifiable survey checkpoints, which is not always possible with elevation data. No photo-identifiable areas could be found in the lidar intensity imagery and horizontal accuracy could not be computed for the lidar data. The lidar data is compiled to meet the 1.0 m RMSE horizontal accuracy specification through rigorous processing of airborne GPS and IMU, use of control, and calibration procedures.

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.

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 DEMs was verified by Dewberry with 8 control points pulled from the topographic part of the job. All 8 points are open terrain points.

The vertical accuracy is tested by comparing control points to the final topobathymetric DEM surface and extracting the elevation of the DEM pixel that contains the xy location of each control point.

Control points in open terrain, bare earth, or urban areas will be used to compute the Fundamental Vertical Accuracy (FVA). Project specifications require a FVA of 0.196 m at the 95% confidence level based on RMSEz (0.125 m) x 1.9600.

As the control points were open terrain points, only the FVA could be verified on this dataset.; Quantitative Value: 0.098 meters, Test that produced the value: Based on the vertical accuracy testing conducted by Dewberry, using NSSDA and FEMA methodology, vertical accuracy at the 95% confidence level (called Accuracyz) is computed by the formula RMSEz x 1.9600. The Puerto Rico Topobathy dataset satisfies the criteria:

DEM dataset tested 0.098 m vertical accuracy at 95% confidence level in open terrain, based on RMSEz (0.050 m) x 1.9600.

Since only 8 points are used for this calculation this result is not statistically significant.

Completeness Report:

Data covers the 5,721 tiles (500m x 500m tiles).

Conceptual Consistency:

Not applicable

Lineage

Process Steps

Process Step 1

CC ID: 632462
Description:

Data for the Puerto Rico Topobathy lidar project was acquired by NOAA using a Riegl VQ-820G Topobathy lidar systems. All delivered lidar data is referenced to:

Horizontal Datum-NAD83 (2011) epoch: 2010

Projection-UTM Zone 19

Horizontal Units-meters

Vertical Datum-NAD83 (2011) epoch: 2010 (ellipsoid heights)

Vertical Units-meters

This dataset encompasses 5,721 500m x 500m tiles in Puerto Rico and Rhode Island. Both green lidar data and NIR lidar data (used for water surface model creation that is incorporated during refraction of the green bathymetric data) was acquired.

NOAA acquired and calibrated the lidar data.

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 Delta-Z (DZ) orthos created in GeoCue software.

Dewberry used E-Cognition to create 2D breaklines representing land/water interfaces. These 2D breaklines were manually reviewed and adjusted where necessary to ensure all well-defined hydrographic features (at 1:1200-scale) were represented with breaklines. Using TerraScan, all green lidar data within breaklines are classified as water column and a sub-set of these points meeting specific criteria are classified as green water surface points. Using TerraScan, all NIR lidar data within breaklines are classified as water column and a sub-set of these points meeting specific criteria are classified as NIR water surface points.

Dewberry used the green water surface points and NIR water surface points to create water surface models. These models are used in the refraction tool to determine the depth of bathymetric points and are created for single swaths to ensure temporal differences and wave or water surface height variations between flight lines do not impact the refraction of the bathymetric data.

Using the SBET data and the water surface models, all green lidar data classified as water column (data within the breaklines) is refracted using Dewberry's lidar Processor (DLP). Light travels at different speeds in air versus water and its direction of travel or angle is changed or refracted when entering the water column. The refraction tool corrects for this difference by adjusting the depth (distance traveled) and horizontal position (change of angle/direction) of the green lidar data. Using statistics and limited manual review, the output data is verified to ensure the refraction tool functioned properly.

Once all green data has been refracted by flight lines, all flight lines covering each tile are combined into a single 500 m x 500 m tile. As the various flight lines may include data collected at Mean Lower Low Water (MLLW) and higher water (HW), which includes everything that is outside the range of MLLW, any HW refracted data points landward of the MLLW land/water interface were classified to class 18 to ensure these HW bathymetric points were not used when MLLW exposed ground points exist in those locations.

Dewberry used algorithms in TerraScan to create the initial ground/submerged topography surface. Dewberry then performed manual editing to review and improve the final topobathy surface. Locations of temporal differences were resolved using the Temporal Difference Decision Tree approved by NOAA. Polygons marking the locations of large temporal differences are provided as part of the deliverables.

All lidar data was peer-reviewed. Dewberry's internal QC 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 1.2 and point data record format 3.

The final classification scheme is as follows:

1-Unclassified

2-Ground

Process Date/Time: 2016-05-01 00:00:00

Process Step 2

CC ID: 632463
Description:

Dewberry made a copy of the final lidar data and transformed the ellipsoid heights into orthometric heights referenced to NAVD88 using Geoid 12B. lidar data classified as ground (2) and submerged topography (26) were then 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 DEM deliverables will also include tiled DEMs that incorporate the use of a void layer.

Void DEM dataset- The void layer was created in Global Mapper where every bathy bottom point was used to create a grid. The distance or threshold that sets how far Global Mapper can interpolate around each bathy bottom point was set as 2. The higher the interpolation threshold, the more bathy bottom points are connected to create a continuous surface in the Global Mapper grid with fewer areas of NoData. The NoData areas in the Global Mapper grids are exported to polygons. Void polygons greater than 9 square meters are imported into Arc 10.1 Geodatabases where they are incorporated into the terrains as erase features. When the terrains are exported to raster, the void polygons used as an erase in the terrain remain as areas of NoData.

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.

Process Date/Time: 2016-05-01 00:00:00

Catalog Details

Catalog Item ID: 48380
GUID: gov.noaa.nmfs.inport:48380
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-14 14:43+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2018-03-13
Owner Org: OCM
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2018-03-13
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2019-03-13