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Short Citation:
OCM Partners, 2023: 2006 FEMA New Jersey Flood Mitigation Lidar: Middlesex County,

Item Identification

Title: 2006 FEMA New Jersey Flood Mitigation Lidar: Middlesex County
Short Name: nj2006_middlesex_m549_metadata
Status: Completed
Publication Date: 2006-11-15

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 100hz inertial measurement unit corrections Terrapoint'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 1.37m spacing, but effectively is

2.74m with overlap factored. Four returns were recorded for each pulse in addition to an intensity value. GPS Week Time, Flightline number

and scan angle attributes were provided for each LiDAR point. Data is provided as random points, in LAS v1.0 format, classified according

to ASPRS Class Code 1= Undefined, 2=Ground.

Original contact information:

Contact Name: Claude Vickers

Contact Org: Terrapoint USA

Title: Production Manager

Phone: 1-877-80-TERRA



The purpose of this LiDAR data is to produce high accuracy 3D elevation based geospatial products for Middlesex County, New Jersey.



Supplemental Information:

Type Of Scanner = Optech 3100EA

Data Acquisition Height = 1550 meters AGL Scanner

Field Of View = 40 degrees; Scan Frequency = 32.9 Hertz

Pulse Repetition Rate = 71 Kilohertz

Aircraft Speed = 180 Knots

Swath Width = 1128 m

Nominal Ground Sample Distance = 1.37 meters (no overlap)

Number of Returns Per Pulse = 4 (first, last, intermediate)

Distance Between Flight Lines = 564

Format: LAS 1.0

ASPRS Class Code 1=Undefined, 2=Ground

First of many pulse and intermediate returns were not considered in the bare earth ground. Please note that the LiDAR intensity is not

calibrated or normalized. The intensity value is meant to provide relative signal return strengths for features imaged by the sensor.

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


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
None ASPRS standards
None OPTECH_3100EA

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
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.

Support Roles

Data Steward

CC ID: 680623
Date Effective From: 2006-11-15
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


CC ID: 680625
Date Effective From: 2006-11-15
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Metadata Contact

CC ID: 680626
Date Effective From: 2006-11-15
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Point of Contact

CC ID: 680624
Date Effective From: 2006-11-15
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1138882
W° Bound: -74.632358
E° Bound: -74.201558
N° Bound: 40.610366
S° Bound: 40.249866

Extent Group 1 / Time Frame 1

CC ID: 1138881
Time Frame Type: Range
Start: 2006-10-08
End: 2006-10-11

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:;

Data Access Constraints:


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: 741727
Download URL:
File Name: Customized Download

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Distribution 2

CC ID: 741728
Download URL:
File Name: Bulk Download

Simple download of data files.

Activity Log

Activity Log 1

CC ID: 680645
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 680644
Activity Date/Time: 2017-11-14

Converted from FGDC Content Standard for Digital Geospatial Metadata (version FGDC-STD-001-1998) using '' script. Contact Tyler Christensen (NOS) for details.

Activity Log 3

CC ID: 718434
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 741729
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality


Raw elevation measurements have been tested at 0.87 feet vertical accuracy at the 95% confidence level.

Horizontal Positional Accuracy:

Compiled to meet 3 ft vertical accuracy at the 95% confidence level.

Vertical Positional Accuracy:

Tested 0.87 ft vertical accuracy at the 95% confidence level.

Completeness Report:

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

-Data completeness and integrity,

-Data accuracy and errors,

-Anomaly checks through full-feature hillshades,

-Post automated classification Bare-earth verification,

-RMSE inspection of final bare-earth model using kinematic GPS,

-Final quality control of deliverable products; ensuring integrity; graphical quality; conformance to Terrapoint standards are met

for all delivered products.

Conceptual Consistency:

All LiDAR files delivered were verified and tested to ensure they open and are positioned properly.



Middlesex LiDAR survey

CC ID: 1138876
Publish Date: 2006-11-15
Extent Type: Range
Extent Start Date/Time: 2006-10-06
Extent End Date/Time: 2006-11-15
Citation URL:
Source Contribution:

LiDAR data representing Middlesex County | Type of Source Media: Hard Drive

Process Steps

Process Step 1

CC ID: 1138877

-General Overview:

The Airborne LiDAR survey was conducted using an OPTECH 3100EA flying at a nominal height of 1550 meters AGL with a total angular

coverage of 40 degrees. Flight line spacing was nominally 564 meters, providing overlap of 50% on adjacent flight lines. All of the

lines were flown in a north/south direction for the project.


A Piper Navajo, registration C-GPJT, was used for the survey. This aircraft has a flight range of approximately 4.5 hours and was

flown at an average altitude of 1550 meters AGL (Above Ground Level), thereby encountering flying altitudes of approximately 1550

meters above Mean Sea Level (MSL). The aircraft was staged from the Linden, NJ Airport, and ferried daily to the project site for

flight operations.

-GPS Receivers

A combination of Sokkia GSR 2600 and NovAtel DL-4+ 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 4 missions were flown for this project with flight times ranging approximately 16.25 hours under good meteorological and

GPS conditions. 55 flight lines were flown over the project area to provide complete coverage. Lines were flown at 564 meter spacing

to achieve 50% lateral overlap.

Process Date/Time: 2006-10-01 00:00:00

Process Step 2

CC ID: 1138878

-Airborne GPS Kinematic

Airborne GPS kinematic data was processed on-site using GrafNav kinematic On-The-Fly (OTF) software. Flights were flown with a minimum

of 6 satellites in view (13 degrees above the horizon) and with a PDOP of better than 4.5. Distances from base station to aircraft were kept

to a maximum of 35 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 5 cm average but no larger than 8 cm being recorded.

-Calculation of 3D laser points (raw data)

The post-processing software o derive X,Y,Z values from roll, pitch, yaw and range is Optech's Realm.

-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 encompassing the entire project areas. The 3D laser point

clouds, in binary format, were imported into the TerraScan project and divided in 425 tiles, as per the contract specifications. 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 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 reviewed by a supervisor via manual inspection and through the

use of a hillshade mosaic of the entire project area.

-Projection Transformation

The data was processed in the native UTM zone in meters and then transformed to the New Jersey State Plane final projection system and US survey

feet using an in-house transformation software which utilizes Corpscon DLL.

Process Date/Time: 2006-11-01 00:00:00

Process Step 3

CC ID: 1138879

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 New Jersey State Plane (NAD83) coordinates, and referenced to the orthometric datum NAVD88 using Geoid 03.

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

1. The data were converted from New Jersey State Plane (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 sorted by latitude and the headers were updated.

Process Date/Time: 2010-09-25 00:00:00

Catalog Details

Catalog Item ID: 49855
GUID: gov.noaa.nmfs.inport:49855
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