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Short Citation:
OCM Partners, 2022: 2008 USGS New Jersey Lidar: Somerset County, https://www.fisheries.noaa.gov/inport/item/49857.

Item Identification

Title: 2008 USGS New Jersey Lidar: Somerset County
Short Name: nj2008_somerset_m545_metadata
Status: Completed
Publication Date: 2008-05-01
Abstract:

These data support the general geospatial needs of the USGS and other federal agencies. LiDAR data is remotely sensed high-resolution elevation

data collected by an airborne collection platform. By positioning laser range finding with the use of 1 second GPS with 200hz inertial measurement

unit corrections, Airborne 1's LiDAR instruments are able to make highly detailed geospatial elevation products of the ground, man-made structures

and vegetation. The LiDAR flightlines for this project were planned for a 50% acquisition overlap. The nominal resolution of this project without

overlap is 1.203m, with a 0.90m resolution with the 50% overlap, assuming a normal distribution. Two returns were recorded for each pulse in addition

to an intensity value. GPS Week Time, Intensity, Flightline and number attributes were recorded for each LiDAR point. Positional values were recorded

to the centimeter level, while GPS is recorded to a 10th of a millisecond. Scan angle was recorded to the nearest angle, Intensity is recorded as a

12 Bit dynamic range value and echo is recorded as a numeric value from 0 to 256.

The data was originally provided as random points, in LAS v1.1 format, classified according to the following codes:

Class 1 Non-ground/Extracted Features Last Pulse

Class 2 Bare Earth Ground Features Last Pulse

Class 3 Extracted Features First Pulse

Class 4 Bare Earth Ground Features First Pulse

It should be noted that Class 3 and 4 are not ASPRS classes but since this data is a two pulse system, this is the most efficient format to

separate the pulses and classification process.

The data was reclassified into 2 distinct classifications:

Class 1 Non-ground/Extracted Features First and Last Pulse

Class 2 Bare Earth Ground Features First and Last Pulse

Purpose:

This data was collected to support geospatial analysis of Somerset County, New Jersey.

Notes:

10501

Supplemental Information:

a) Nominal Pulse density = The nominal resolution of this project without overlap is 1.203m.

b) Calibration procedures =

- General Overview:

The Airborne LiDAR survey was conducted using one OPTECH 2050 systems flying at a nominal height of 1370 meters AGL a total angular coverage

of 40 degrees. Flight line spacing nominally 639 meters providing overlap of 50% on adjacent flight lines. Lines were flown in N/S directions

to best optimize flying time considering the layout for the project. Distances from base station to aircraft (differential baselines) were kept to a

maximum of 30 km while the mean is 6.8 km. The aircraft was a Cessna Caravan, registration N682AC, was used for the survey. This aircraft has a

flight range of approximately 13.5 hours and was flown at an average altitude 1370 meters above ground level (AGL). The aircraft was staged from the

Morristown and Princeton Airports and ferried daily to the project site for flight operations.

Aircraft Speed = 110 Knots

Number of Scanners = 1

Swath Width = 1278.01 m Nominal

Distance Between Flight Lines = 639m

Data Acquisition Height = 1370 meters AGL

Pulse Repetition Rate = 50 Kilohertz

Number of Returns Per Pulse = 2

Scanner Field of View = 40 degrees

Frequency of Scan = 28 Hertz

Beam Divergence = Narrow

- GPS Receivers:

A combination of Leica 500 Series and Applanix POSAv-410 dual frequency GPS receivers were used to support the airborne operations of this survey

and to establish the GPS control network.

- Number of Flights and Flight Lines:

A total of 3 missions were flown for this project with flight time ranging approximately 3.5 hours under good meteorological and GPS conditions.

51 flight lines were flown over the project site to provide complete coverage.

- Reference Coordinate System Used:

Existing NGS (National Geodetic Survey) monuments were observed as control base stations in a GPS control network - PIDs AG9916 and KV1189. AG9916

and KV1189 were occupied as primary control for the project flight missions and kinematic ground surveys. The published horizontal datum of the NGS

stations is NAD83 and the vertical datum NAVD88. The following are the final coordinates of the newly established control points used in this project:

Station_PID: AG9916

West_Longitude: -074 26 46.04499

North_Latitude: 40 33 26.21313

Ellips_Elev: -7.771m

Station_PID: KV1189

West_Longitude: -074 43 48.85846

North_Latitude: 40 36 22.24551

Ellips_Elev: -7.771m

- Geoid Model Used:

The Geoid03 geoid model, published by the NGS, was used to transform all ellipsoidal heights to orthometric.

The Lidar QA/QC Quantitative and Qualitative Assessment Report for this data set may be viewed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/545/supplemental/lidarqaqcreport_somerset_final.pdf

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/545/supplemental/2008_USGS_NJ_Lidar_Somerset_County.kmz

Keywords

Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
elevation

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
Entity Attribute Overview:

Attributes present in the data set (Precision reported in brackets) = X<Y<Z (0.01), Class (Integer), GPS WeekTime (0.0001 seconds),

Easting (0.01 meter), Northing (0.01 meter), Elevation (0.01 meter), Echo Number (Integer 1 to 2), Echo (Integer 1 to 2),

Intensity (12 Bit Dynamic), Flightline, Scan Angle (Integer Degree).

Entity Attribute Detail Citation:

LiDAR point data in LAS 1.1 ASPRS classification scheme Class 1 Non-ground/Extracted Features Last Pulse; Class 2 Bare Earth Ground Features

Last Pulse; Class 3 All Shots First Pulse; Class 7 Noise.

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: Acknowledgment of the U.S. Geological Survey would be appreciated for products derived from these data.

Support Roles

Data Steward

CC ID: 680689
Date Effective From: 2008-05-01
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: 680691
Date Effective From: 2008-05-01
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: 680692
Date Effective From: 2008-05-01
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: 680690
Date Effective From: 2008-05-01
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: 1138838
W° Bound: -74.798045
E° Bound: -74.499545
N° Bound: 40.758506
S° Bound: 40.373106

Extent Group 1 / Time Frame 1

CC ID: 1138837
Time Frame Type: Discrete
Start: 2008-02-01

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;

Data Access Constraints:

None

Data Use Constraints:

Users should be aware that temporal changes may have occurred since this data set was collected and that 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: 741733
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=545
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: 741734
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/545/index.html
Distributor:
File Name: Bulk Download
Description:

Simple download of data files.

URLs

URL 1

CC ID: 741736
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 741737
URL: https://coast.noaa.gov
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 680709
Activity Date/Time: 2017-03-20
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 680708
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: 718436
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 741735
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Data Quality

Accuracy:

According to Airborne 1 standards; the following aspects of the LiDAR data was verified during the course of the project processing:

-Data accuracy and errors

-Anomaly checks through full-feature hillshades and 3-D modeling

-Post automated classification Bare-earth verification

-Final quality control of deliverable products ensuring integrity, graphical quality

Horizontal Positional Accuracy:

Compiled to meet 0.5m horizontal accuracy at the 95 percent confidence level

Vertical Positional Accuracy:

Independent accuracy testing was performed by Dewberry using high accuracy quality control checkpoints distributed around Somerset County

on near level open bare terrain and near level vegetated terrain. Dewberry uses testing procedures consistent with those specified in the National

Standard for Spatial Data Accuracy (NSSDA). The Bare Earth RMSEz is 0.06m compared to the specified 0.15m for accuracy. This number represents the

combined vertical accuracy of 40 individual open terrain (RMSEz = 0.058m) and urban (RMSEz = 0.063m) checkpoints. The RMSEz for Vegetation is 0.10m

compared to the specified 0.27m for accuracy. This represents the combined vertical accuracy of 20 individual vegetated (plant heights between

1 and 5 ft; RMSEz = 0.119m) and forested (plant heights greater than 5 ft; RMSEz = 0.083m) checkpoints.

; Quantitative Value: 0.114 meters, Test that produced the value:

National Standard for Spatial Data Accuracy. Using NSSDA standards, this LiDAR dataset was tested 0.114m fundamental vertical accuracy

at 95% confidence level, compared to 0.363m for 2ft equivalent contour.

Completeness Report:

According to Airborne 1 standards, data completeness and integrity was verified. Conformance to Airborne 1 standards are met for all delivered products.

Conceptual Consistency:

All LAS formatted LiDAR data are validated to ensure that data on delivery media is in correct physical format and is readable and correctly

georeferenced and projected. Note that LiDAR intensity is not calibrated or normalized.

Lineage

Process Steps

Process Step 1

CC ID: 1138833
Description:

> Airborne GPS Kinematic

Airborne GPS kinematic data was post processed at Airborne 1 facilities using POS-GNSS kinematic On-The-Fly (OTF) software. Flights were flown

with a minimum of 6 satellites in view (13o above the horizon) and with a PDOP of better than 3.5. Distances from base station to aircraft

(differential baselines) were kept to a maximum of 31 km while the mean is 16 km, to ensure a strong OTF (On-The-Fly) solution. For all flights,

the GPS data can be classified as excellent, with GPS residuals of 5cm average but no larger than 10 cm being recorded.

>Generation and Calibration of laser points (raw data)

The initial step of calibration is to verify availability and status of all needed GPS and Laser data against field notes and compile any data

if not complete. Subsequently the mission points are output using Optech's REALM, initially with default values from Optech or the last mission

calibrated for system. The initial point generation for each mission calibration is verified within Microstation/Terrascan for calibration

errors. If a calibration error greater than specification is observed within the mission, the roll pitch and scanner scale corrections that need

to be applied are calculated. The missions with the new calibration values are regenerated and validated internally once again to ensure quality.

All missions are validated against the adjoining missions for relative vertical biases and collected GPS kinematic ground truthing points for

absolute vertical accuracy purposes. On a project level, a coverage check is carried out to ensure no slivers are present.

>Data Classification and Editing

The data was processed using the software TerraScan, and following the methodology described herein. The initial step is the setup of the

TerraScan project, which is done by importing client provided tile boundary index (converted to the native UTM zone for processing)encompassing

the entire project areas. The 3D laser point clouds, in binary format, were imported into the TerraScan project and divided in 409 Tiles as

specified by 133 Urban Area Ortho tiles in LAS 1.0 format. Once tiled, the laser points were classified using a proprietary routine in TerraScan.

This routine removes any obvious outliers from the dataset following which the ground layer is extracted from the point cloud. The ground

extraction process encompassed in this routine takes place by building an iterative surface model. This surface model is generated using three main

parameters: building size, iteration angle and iteration distance. The initial model is based on low points being selected by a "roaming window"

with the assumption is that these are the ground points. The size of this roaming window is determined by the building size parameter. The low

points are triangulated and the remaining points are evaluated and subsequently added to the model if they meet the iteration angle and distance

constraints. This process is repeated until no additional points are added within an iteration. A second critical parameter is the maximum terrain

angle constraint, which determines the maximum terrain angle allowed within the classification model. The data is then manually quality controlled

with the use of hillshading, cross-sections and profiles. Any points found to be of class vegetation, building or error during the quality control

process, are removed from the ground model and placed on the appropriate layer. An integrity check is also performed simultaneously to verify that

ground features such as rock cuts, elevated roads and crests are present. Once data has been cleaned and complete, it is then by a supervisor via

manual inspection and through the use of a hillshade mosaic of the entire project area.

Process Date/Time: 2008-02-01 00:00:00

Process Step 2

CC ID: 1138834
Description:

>Deliverable Product Generation

-Deliverable Tiling Scheme

All files were converted to LAS 1.1, in the specified projection and units and were delivered in the client provided tiling scheme with a

total of 409 tiles.

-LAS 1.1 Files

LiDAR point data in LAS 1.1, classified according to the following classification scheme:

Class 1 Non-ground/Extracted Features Last Pulse

Class 2 Bare Earth Ground Features Last Pulse

Class 3 Extracted Features First Pulse

Class 4 Bare Earth Ground Features First Pulse

The data contains the following fields of information (Precision reported in brackets):

Class (Integer), GPS WeekTime (0.0001 seconds), Easting (0.01 meter), Northing (0.01 meter), Elevation (0.01 meter), Echo Number (Integer 1 to 2),

Echo (Integer 1 to 2), Intensity (12 Bit Dynamic), Flightline, Scan Angle (Integer Degree)

All points outside project area were assigned to Class 1 - Non-Ground.

-GPS Trajectory Files

GPS Trajectory Files were provided in digital copy

-ABGPS/IMU Positions

ABGPS/IMU combined files containing time,x,y,z,kappa,phi,omega were provided in ASCII format. All positions were provided in NAD83 UTM18,

NAVD88(Geoid03), GPS seconds (reported to a 10th of a millisecond), meters (reported to a centimeter) for the XYZ and degrees for the

kappa,phi,omega (reported to 6 decimals of a degree).

Process Date/Time: 2008-02-01 00:00:00

Process Step 3

CC ID: 1138835
Description:

The NOAA Office for Coastal Management (OCM) received the files in las format. The files contained Lidar elevation and intensity measurements.

The data were in projected in UTM coordinates, Zone 18 (NAD83), and referenced to the orthometric datum of NAVD88 utilizing Geoid 03.

OCM performed the following processing to the data to make it available within the Digital Coast:

1. The data were converted from UTM Zone 18 (NAD83) coordinates to geographic coordinates (NAD83).

2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 03.

3. The LAS data were reclassifed from 4 to 2 classes:

- Class 1, Non-ground/Extracted Features Last Pulse; Extracted Features First Pulse

- Class 2, Bare Earth Ground Features Last Pulse; Bare Earth Ground Features First Pulse

4. The LAS data were sorted by latitude and the headers were updated.

Process Date/Time: 2010-08-27 00:00:00

Catalog Details

Catalog Item ID: 49857
GUID: gov.noaa.nmfs.inport:49857
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:22+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: 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