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Short Citation:
OCM Partners, 2023: 2018 USGS Lidar: Post Hurricane Maria - USVI, https://www.fisheries.noaa.gov/inport/item/60110.

Item Identification

Title: 2018 USGS Lidar: Post Hurricane Maria - USVI
Status: Completed
Publication Date: 2018-12-14
Abstract:

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 301 individual 1500 m x 1500 m tiles; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

Geographic Extent: St. Croix, US Virgin Islands, covering approximately 82 square miles & St. Thomas and St. John, US Virgin Islands, covering approximately 52 square miles.

Dataset Description: PR USVI Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3. The data was developed based on a horizontal projection/datum of NAD83 (2011), Puerto Rico and Virgin Islands, meters and vertical datum of VIVD09 (GEOID12B), meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 143 individual 1500 m x 1500 m tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1500 m x 1500 m schema.

Ground Conditions: Lidar was collected in late 2018, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Leading Edge Geomatics established a total of 4 ground control points that were used to calibrate the lidar to known ground locations established throughout the St. Croix, US Virgin Islands project area. An additional 28 independent accuracy checkpoints, 22 in Bare Earth and Urban landcovers (22 NVA points), 6 in Tall Grass and Brushland/Low Trees categories (6 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

Purpose:

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 0.5 meter cell size. These raw lidar point cloud data were used to create classified lidar LAS files, intensity images, 3D breaklines, hydro-flattened DEMs as necessary.

Supplemental Information:

USGS Contract No. G16PC00020 CONTRACTOR: Dewberry SUBCONTRACTOR: Leading Edge Geomatics Lidar data were acquired and calibrated by Leading Edge Geomatics. All follow-on processing was completed by the prime contractor.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v1.3",

"ldrsens" : "Riegl VQ1560i",

"ldrmaxnr" : "Infinite",

"ldrnps" : "0.31",

"ldrdens" : "10.3",

"ldranps" : "0.31",

"ldradens" : "10.3",

"ldrfltht" : "1000",

"ldrfltsp" : "150",

"ldrscana" : "57",

"ldrscanr" : "175x2",

"ldrpulsr" : "700x2",

"ldrpulsd" : "3",

"ldrpulsw" : "0.8994",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1086",

"ldrswato" : "20",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12B"

},

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v1.3",

"ldrsens" : "Riegl Q780",

"ldrmaxnr" : "Infinite",

"ldrnps" : "0.42",

"ldrdens" : "5.7",

"ldranps" : "0.30",

"ldradens" : "11.4",

"ldrfltht" : "800",

"ldrfltsp" : "100",

"ldrscana" : "60",

"ldrscanr" : "122",

"ldrpulsr" : "400",

"ldrpulsd" : "3",

"ldrpulsw" : "0.8994",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "924",

"ldrswato" : "50",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12B"

},

"ldraccur" : {

"ldrchacc" : "0.341",

"rawnva" : "0.148",

"rawnvan" : "91",

"clsnva" : "0.132",

"clsnvan" : "96",

"clsvva" : "0.270",

"clsvvan" : "71"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.",

"lasolap" : "Swath "overage" points were identified in these files using the standard LAS overlap bit.",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare Earth Ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Ground"

}

}}

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
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 > COASTAL ELEVATION
ISO 19115 Topic Category
elevation

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > SEA FLOOR
UNCONTROLLED
Global Change Master Directory (GCMD) Location Keywords U.S. Coastline
Global Change Master Directory (GCMD) Location Keywords US Virgin Islands
None St. John
None St. Thomas

Instrument Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
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: USGS, Dewberry

Support Roles

Data Steward

CC ID: 912878
Date Effective From: 2020
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: 912877
Date Effective From: 2020
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: 912879
Date Effective From: 2020
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: 912880
Date Effective From: 2020
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: 1144657
W° Bound: -65.091258
E° Bound: -64.557106
N° Bound: 18.417612
S° Bound: 17.670113

Extent Group 1 / Time Frame 1

CC ID: 1144656
Time Frame Type: Range
Start: 2018-05-13
End: 2018-06-08

Spatial Information

Spatial Representation

Representations Used

Grid: No
Vector: Yes
Text / Table: No
TIN: No
Stereo Model: No
Video: No

Vector Representation 1

CC ID: 912892
Point Object Present?: Yes
Point Object Count: 24683185118

Access Information

Security Class: Unclassified
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

CC ID: 912881
Start Date: 2020-06-22
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9114/details/9114
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2020 - 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: Zip
Compression: Zip

Distribution 2

CC ID: 912882
Start Date: 2020-06-22
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9114/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2020 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

File Type: LAZ
Compression: Zip

URLs

URL 1

CC ID: 912883
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
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 2

CC ID: 912884
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9114/supplemental/extent_PR_VI_2018_m9114.kmz
Name: Browse graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

URL 3

CC ID: 912885
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9114/supplemental/Appendix_A_Survey_Report.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

URL 4

CC ID: 912886
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9114/supplemental/Appendix_B_Ground_Control_Survey_Report.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

URL 5

CC ID: 912887
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9114/supplemental/PR_USVI_Lidar_2018_Project_Report.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

URL 6

CC ID: 912888
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9114/supplemental/Appendix_D_GPS_Processing.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

Data Quality

Horizontal Positional Accuracy:

The island of Puerto Rico and its surrounding islands were 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. Seventeen (17) checkpoints were photo-identifiable but do not produce a

statistically significant tested horizontal accuracy value. Using this small sample set of photo identifiable checkpoints, positional accuracy of this dataset was found to be RMSEx = 15.5 cm

and RMSEy = 12.2 cm which equates to +/- 34.1 cm at 95% confidence level. While not statistically significant, the results of the small sample set of checkpoints are within the produced to meet horizontal accuracy

Vertical Positional Accuracy:

For St. Croix, the tested RMSEz of the classified lidar data for checkpoints in non-vegetated terrain equaled 6.6 cm compared with the 10 cm specification; and the NVA of the classified lidar data computed using RMSEz x 1.9600 was equal to 12.9 cm, compared with the 19.6 cm specification.

For St. Croix, the tested VVA of the classified lidar data computed using the 95th percentile was equal to 9.5 cm, compared with the 29.4 cm specification.

For St. John and St. Thomas, the tested RMSEz of the classified lidar data for checkpoints in non-vegetated terrain equaled 5.2 cm compared with the 10 cm specification; and the NVA of the classified lidar data computed using RMSEz x 1.9600 was equal to 10.2 cm, compared with the 19.6 cm specification.

For St. John and St. Thomas, the tested VVA of the classified lidar data computed using the 95th percentile was equal to 11.1 cm, compared with the 29.4 cm specification. Additional accuracy information and statistics for the classified lidar data, raw swath data, and bare earth DEM data are found in the following sections of this report.

The project specifications require that only Non-Vegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The required accuracy (ACCz) is: 19.6 cm at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 10 cm in the "bare earth" and "urban" land cover classes. The NVA of Puerto Rico, the U.S. Virgin Islands, and the surrounding islands will be tested with 91 checkpoints located in bare earth and urban (non-vegetated) areas. These check points were not used in the calibration or post processing of the lidar point cloud data. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See survey report for additional survey methodologies.

Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control points. AccuracyZ will be tested to meet 19.6 cm or better Non-Vegetated Vertical Accuracy at 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

Completeness Report:

Datasets contain complete coverage of tiles. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. There are no void areas or missing data. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Conceptual Consistency:

Data covers the entire area specified for this project.

Data Management

Have Resources for Management of these Data Been Identified?: Yes
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

Processed Lidar

CC ID: 1144651
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Dewberry

Process Steps

Process Step 1

CC ID: 1144652
Description:

The boresight for each lift was done individually as the solution may change slightly from lift to lift. The following steps describe the Raw Data Processing and Boresight process: 1) Technicians processed the raw data to LAS format flight lines using the final GPS/IMU solution. This LAS data set was used as source data for boresight. 2) Technicians first used Riegl software to calculate initial boresight adjustment angles based on sample areas selected in the lift. These areas cover calibration flight lines collected in the lift, cross tie and production flight lines. These areas are well distributed in the lift coverage and cover multiple terrain types that are necessary for boresight angle calculation. The technician then analyzed the results and made any necessary additional adjustment until it is acceptable for the selected areas. 3) Once the boresight angle calculation was completed for the selected areas, the adjusted settings were applied to all of the flight lines of the lift and checked for consistency. The technicians utilized commercial and proprietary software packages to analyze how well flight line overlaps match for the entire lift and adjusted as necessary until the results met the project specifications. 4) Once all lifts were completed with individual boresight adjustment, the technicians checked and corrected the vertical misalignment of all flight lines and also the matching between data and ground truth. The relative accuracy was less than or equal to 6 cm RMSEz within individual swaths and less than or equal to 8 cm RMSEz or within swath overlap (between adjacent swaths). 5) The technicians ran a final vertical accuracy check of the boresighted flight lines against the surveyed check points after the z correction to ensure the requirement of NVA = 19.6 cm 95% Confidence Level (Required Accuracy) was met. Point classification was performed according to USGS Lidar Base Specification 1.3, and breaklines were collected for water features. Bare earth DEMs were exported from the classified point cloud using collected breaklines for hydroflattening.

Process Step 2

CC ID: 1144653
Description:

LAS Point Classification: The point classification is performed as described below. The bare earth surface is then manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through heads-up digitization. All ground (ASPRS Class 2) lidar data inside of the Lake Pond, Tidal, and Double Line Drain hydro flattening breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 0.35 meters was also used around each hydro-flattened feature to classify these ground (ASPRS Class 2) points to Ignored ground (ASPRS Class 20). All Lake Pond Island, Tidal, and Double Line Drain Island features were checked to ensure that the ground (ASPRS Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to approved classes by USGS. The overlap data was classified using standard LAS overlap bit. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS through numerous conference calls and pilot study areas. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper us used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Proprietary software was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.

Process Date/Time: 2018-12-10 00:00:00

Process Step 3

CC ID: 1144654
Description:

The NOAA Office for Coastal Management (OCM) downloaded this data set from these USGS sites:

ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/ /USGS_LPC_PR_PRVI_VI_B1_2018/ USGS_LPC_PR_PRVI_VI_B1_2018/

The total number of LAZ files downloaded and processed was 301.

The data were in Puerto Rico/USVI State Plane (3500) (NAD83 2011), meters coordinates and VIVD09 (Geoid12B) elevations in meters.From the provided report, the data were classified as:

1 - Unclassified

2 - Ground

7 - Low Noise

9 - Water

17 - Bridge Decks

18 - High Noise

20 - Ignored Ground due to Breakline Proximity

OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available in the DAV are: 1, 2, 7, 9, 17, 18 & 20.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges.

2. Internal OCM scripts were run on the laz files to convert from orthometric (VIVD09) elevations to ellipsoid elevations using the Geoid12B model, to convert to geographic coordinates, to assign the geokeys, to sort the data by gps time and zip the data to database and to http.

Process Contact: Office for Coastal Management (OCM)

Catalog Details

Catalog Item ID: 60110
GUID: gov.noaa.nmfs.inport:60110
Metadata Record Created By: Blake Waring
Metadata Record Created: 2020-06-23 10:24+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-08-15 17:09+0000
Metadata Record Published: 2022-03-16
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16