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Short Citation:
OCM Partners, 2023: 2006 FEMA Lidar: Rhode Island Coastline,

Item Identification

Title: 2006 FEMA Lidar: Rhode Island Coastline
Short Name: ri2006_fema_coastal_m2570_metadata
Status: Completed
Publication Date: 2014-12-10

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 100 hz inertial measurement unit corrections; Terrapoint 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 was planned for a 50 percent acquisition overlap. The nominal resolution of this project without overlap is 1.25 m. Four returns were recorded for each pulse in addition to an intensity value. GPS Week Time, Intensity, Flightline and number attributes were provided for each LiDAR point.

Data is provided as random points, in LAS format, classified according to ASPRS Class Code 2=Ground 1=Undefined.


The purpose of this LiDAR data was to produce high accuracy 3D elevation based geospatial products for coastal flood mapping. The following regions of Rhode Island are included in this project:

New Shoram - 29 square kilometers, North Kingston - 30 square kilometers, Westerly Charleston - 60 square kilometers



Other Citation Details:

Project Area = 119 square kilometers

Type Of Scanner = Optech 3100EA

Data Acquisition Height = 1550 meters AGL

Scanner Field Of View = 46 degrees

Scan Frequency = 30.8 Hertz

Pulse Repetition Rate = 71 Kilohertz

Aircraft Speed = 150 Knots

Swath Width = 1316 m

Nominal Ground Sample Distance = 1.25 meters (no overlap)

Number of Returns Per Pulse = 4 (last)

Distance Between Flight Lines = 658m

Supplemental Information:

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

The project report of this data set may be viewed in Google Earth at:

The survey report of this data set may be viewed in Google Earth at:


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
None Land Surface

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: las
Entity Attribute Overview:

LiDAR point data in LAS 1.0 format

ASPRS cassfication scheme (1 = undefined; 2 = ground) contains the following fields of information:

Class, GPS WeekTime, Easting, Northing, Elevation, Echo, Number, Echo, Intensity, Flightline

Entity Attribute Detail Citation:


Distribution Liability:

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

Support Roles

Data Steward

CC ID: 684787
Date Effective From: 2014-12-10
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: 684789
Date Effective From: 2014-12-10
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: 684790
Date Effective From: 2014-12-10
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: 684788
Date Effective From: 2014-12-10
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: 1134681
W° Bound: -71.898698
E° Bound: -71.401523
N° Bound: 41.654748
S° Bound: 41.146134

Extent Group 1 / Time Frame 1

CC ID: 1134680
Time Frame Type: Range
Start: 2006-12-16
End: 2006-12-18

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:

Any conclusions from results of the analysis of this LiDAR are not the responsibility of Terrapoint. The LiDAR data was thoroughly visually verified to represent the true ground conditions at time of collection. Users should be aware of this limitations of this dataset if using for critical applications.

Distribution Information

Distribution 1

CC ID: 742292
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: 742293
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 742295
URL Type:
Online Resource


CC ID: 742296
URL Type:
Online Resource


CC ID: 742297
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the lidar coverage for the 2006 FEMA project for the coastal regions of Rhode Island in Washington County.

Activity Log

Activity Log 1

CC ID: 684804
Activity Date/Time: 2016-07-28

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 684803
Activity Date/Time: 2017-11-14

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

Activity Log 3

CC ID: 718556
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 742294
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality

Horizontal Positional Accuracy:

Compiled to meet 3 foot horizontal accuracy at the 95 percent confidence level (near 1.0 m)

Vertical Positional Accuracy:

0.2; Quantitative Value: 0.2 meters, Test that produced the value: Tested 0.39 feet vertical accuracy at 95 percent confidence level using Terrapoint internal check points.

Dewberry independently tested this LiDAR dataset 0.20 ft vertical accuracy at 95% confidence level in open terrain, based on open terrain RMSEz (0.10ft) x 1.9600; tested 0.35ft vertical accuracy at 95% confidence level in all land cover categories combined, based on consolidated RMSEz (0.18ft) x 1.9600.

Completeness Report:


Conceptual Consistency:

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


Process Steps

Process Step 1

CC ID: 1134675

- 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 (13o 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 5cm average but no larger than 12 cm being recorded.

- Calculation of 3D laser points (raw data)

The post-processing software to 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 325 tiles, as per the contract specifications. 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 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 Rhode Island State Plane final projection system and US survey feet using an in-house transformation software which uses the Coorpscon DLL.

Process Date/Time: 2007-02-01 00:00:00

Process Step 2

CC ID: 1134676

- 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. Lines were flown in east/west and north/south orientated blocks to best optimize flying time considering the layout for the project.

- Aircraft

A Piper Navajo, registration C-FQQB was used for the survey. This aircraft has a flight range of approximately 6.5 hours and was flown at an average altitude of 1550, thereby encountering flying altitudes of approximately 1550 meters above sea level (ASL). The aircraft was staged from the East Haven CT 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

For both Connecticut and Rhode Island Coastline Sites; a total of 6 missions were flown for this project with flight times ranging approximately 31 hours under good meteorological and GPS conditions. 33 flight lines were flown over the Connecticut Coastline site to provide complete coverage.

Process Date/Time: 2006-12-01 00:00:00

Process Step 3

CC ID: 1134677

Quantitative vertical positional accuracy assessment:

Independent accuracy testing was performed by Dewberry & Davis using 20 high accuracy quality control checkpoints distributed throughout the project in four major land cover types (open terrain, weeds/crops, forest, urban) . Dewberry used testing procedures consistent with those specified in the National Standard for Spatial Data Accuracy (NSSDA) as well as LiDAR accuracy testing guidelines and specifications published by the Federal Emergency Management Agency (FEMA), National Digital Elevation Program (NDEP), and American Society for Photogrammetry and Remote Sensing (ASPRS).

Process Date/Time: 2007-08-01 00:00:00

Process Step 4

CC ID: 1134678

The NOAA Office for Coastal Management (OCM) received topographic LAS files as part of the USGS CLICK elevation data shipment. The files contained lidar easting, northing, elevation, as well as ancillary collection attributes. The data were received in Rhode Island State Plane Zone 3800, NAD83 coordinates and were vertically referenced to NAVD88 using the Geoid03 model. The vertical and horizontal units of the data were in U.S. feet. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The LAS files were converted from feet to meters, removing erroneous elevations.

2. The LAS files were converted from orthometric (NAVD88) heights to ellipsoidal heights using the Geoid03 model.

3. The LAS files were converted from a Projected Coordinate System (RI Zone 3800h) to a Geographic Coordinate system with decimal degree units.

Process Date/Time: 2007-08-01 00:00:00

Catalog Details

Catalog Item ID: 49956
GUID: gov.noaa.nmfs.inport:49956
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:23+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