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Short Citation:
OCM Partners, 2024: 2012 USACE Post Sandy Topographic LiDAR: Rhode Island and Massachusetts Coast,

Item Identification

Title: 2012 USACE Post Sandy Topographic LiDAR: Rhode Island and Massachusetts Coast
Short Name: 2012_USACE_PostSandy_MA_RI_lidar_m1435_metadata
Status: Completed
Publication Date: 2013-01

This topographic elevation point data derived from multiple return light detection and ranging (LiDAR) represents 354.272 square miles of coastline for Rhode Island and Massachusetts.

The LiDAR point cloud is delivered in LAS 1.2 format with the following classifications:

Class 1: Unclassified

Class 2: Ground

Class 9: Water

Class 10: Ignored Points

Class 12: Overlap

Original contact information:

Contact Name: Steve Newman

Contact Org: ERDC-CRREL, RS/GIS and Water Branch

Phone: (603) 646-4372



HQ, USACE required digital elevation data to generate digital elevation models and contours for use in: damage assessment to USACE projects, engineering design and design reviews,

conservation planning, research, delivery, floodplain mapping and hydrologic modeling using LiDAR technology.



Supplemental Information:

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


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
Keywords Bathymetry/Topography
Keywords Elevation
Keywords LAS
Keywords LiDAR

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: As Needed
Data Presentation Form: las
Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility

of Magnolia River, USACE, USGS, NOAA, the Office for Coastal Management or its partners.

Support Roles

Data Steward

CC ID: 669712
Date Effective From: 2013-01
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: 669714
Date Effective From: 2013-01
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: 669715
Date Effective From: 2013-01
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: 669713
Date Effective From: 2013-01
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: 1133439
W° Bound: -71.9092352
E° Bound: -69.944377
N° Bound: 41.6023329
S° Bound: 41.1295003

Extent Group 1 / Time Frame 1

CC ID: 1133438
Time Frame Type: Range
Start: 2012-11-11
End: 2012-11-22

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. These data depict the heights at the time of the survey and are only accurate for that time.

Distribution Information

Distribution 1

CC ID: 740313
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: 740314
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 740316
URL Type:
Online Resource


CC ID: 740317
URL Type:
Online Resource


CC ID: 740318
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the post Sandy LiDAR coverage for coastal Connecticut

Activity Log

Activity Log 1

CC ID: 669733
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 669732
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: 718050
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 740315
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality

Horizontal Positional Accuracy:

Expected horizontal accuracy of elevation products for the Optech ALTM 3100 sensor, as determined from system studies and other methods, is 1/2000th of the flight height, which, in the

instance of this particular project was 1,250 meters AGL, giving a horizontal tolerance of less than 0.62 meter.

Vertical Positional Accuracy:

LiDAR Check Points were collected throughout the areas to assess the accuracy of the elevation data. The test points were collected in three land cover categories:

- Open terrain (bare earth) - Marsh and low trees - High trees. Tested 0.214 Meter fundamental vertical accuracy at 95 percent confidence level in open terrain using RMSEz x 1.9600.

Tested 0.350 Meter consolidated vertical accuracy at the 95th percentile in open terrain, marsh/low trees, and treed areas. Tested 0.265 Meter supplemental vertical accuracy at the

95th percentile in treed areas. Tested 0.397 Meter supplemental vertical accuracy at the 95th percentile in marsh and low tree areas.

; Quantitative Value: 0.109 meters, Test that produced the value: RMSE in meters

Completeness Report:

The following methods are used to ensure LiDAR data accuracy:

1) Use of a ground control network utilizing GPS survey techniques

2) Use of airborne GPS and IMU in conjunction with the acquisition of LiDAR

Conceptual Consistency:

Compliance with the accuracy standard was ensured by the collection of ground control and the establishment of a GPS base station at the operation airport. The following checks were performed:

1) The LiDAR data accuracy was validated by checking bare earth data against control and validation points spread throughout the project area.

2) LiDAR flightlines' overlap and edge matching were validated through visual inspection.


Process Steps

Process Step 1

CC ID: 1133428

LIDAR ACQUISITION: A LiDAR survey was conducted between Nov 11 and Nov 22, 2012. An Optech 3100 sensor aboard a Cessna 206/G was utilized for the survey. Flight altitude was planned

at 1,250-meters. See "PROJEC REPORT" for details regarding the flight.

Process Date/Time: 2012-11-01 00:00:00

Process Step 2

CC ID: 1133429

CHECK POINT SURVEY: A GPS survey was conducted to assess the accuracy of the LiDAR data. See "SURVEY REPORT" for details of the check point survey.

Process Date/Time: 2012-11-01 00:00:00

Process Step 3

CC ID: 1133430

LiDAR CALIBRATION: Data collection of the survey area resulted in a total of one-hundred and five flightlines, including eight control lines, covering the project area. The range files, flight logs,

raw air and ground GPS files were then taken to the office for data processing using DashMap v 5.2 (Optech, Inc.). DashMap uses the SBET to generate a set of data points for each laser return in the

LAS file format. Each data point is assigned an echo value so it can be segregated based on the first and last pulse information. This project's data were processed in strip form, meaning each flight

line was processed independently. Processing the lines individually provides the data analyst with the ability to QC the overlap between lines. Each strip was then imported into a project using TerraScan

(Terrasolid, Ltd.) and the project management tool GeoCue (GeoCue Corp.). By creating a project the various flightlines are combined while breaking the dataset as a whole into manageable pieces. This process

also converts the dataset from UTM (NAD83, 2011) to the Geographic Coordinate System (NAD 83, 2011). The ellipsoid height values were converted to NAVD88, Meters, orthometric values using Geoid 12A, provided by

National Geodetic Survey (NGS). Individual lines were then checked against adjacent lines and intersecting control lines to ensure a cohesive dataset.

Process Date/Time: 2012-12-01 00:00:00

Process Step 4

CC ID: 1133431

LiDAR CLASSIFICATION & BREAKLINE COLLECTION: A classification routine was applied to extract the initial surface model. This initial surface model was then reduced using Magnolia Rivers' proprietary methods to create the final

bare-earth dataset. Upon reaching a satisfactory classification result, the bare-earth data were then checked against the control and validation points across the project area. The results of these checks showed the DEM meeting

accuracy requirements. Hydro-Flattening breaklines were collected where necessary to support the final digital elevation models. A Triangular Irregular Network (TIN) was generated using the lidar ground points for each

preliminary tiled deliverable and the breaklines were placed in 2D with each element's height being adjusted to the surface to create a 3D element in the MicroStation (Bentley Systems, Inc.) environment.

Process Date/Time: 2012-12-01 00:00:00

Process Step 5

CC ID: 1133432

INTENSITY IMAGERY: The intensity images were created for this project using GeoCue (version 2012.1.27.5). The images were derived from the full LiDAR point cloud native radiometric intensity values. As per the project

specifications the intensity orthos were produced at a 1-meter pixel size for the entire project. The initial GeoTIFF images were produced in UTM Zone 19N NAD83(2011) and were then transformed (reprojected) to the geographic

coordinate system for delivery using Global Mapper software (version 13.2.2; Blue Marble Geographics) and clipped to the deliverable tile boundaries with an additional 2-meter buffer applied to each tile.

Process Date/Time: 2012-12-01 00:00:00

Process Step 6

CC ID: 1133433

MODEL KEY POINTS: Model key-points were classified (ASPRS Class 8) using the TerraScan (Terrasolid Ltd.) Classify Model Keypoints routine to classify LiDAR points that fell within a specified tolerance of the full resolution

ground model (i.e. all classified ground returns) resulting in a reduced resolution surface model that meets a given accuracy. An accuracy tolerance of 0.15 meters was used for this processing.

Process Date/Time: 2012-12-01 00:00:00

Process Step 7

CC ID: 1133434

DIGITAL ELEVATION MODELS: Digital Elevation Models (DEMs) of the bare earth ground surface were generated using the TerraModeler (Terrasolid Ltd.) software. The DEMs were produced by sampling elevations at a 1-meter posting

from a triangulated irregular network (TIN) model based on all classified ground returns and 3-D breakline features and output as an ESRI ASCII GRID formatted file. These ASCII GRID files were then converted to ESRI Binary

GRID format. Initially, these GRIDs were generated from points and breaklines in the UTM projection (Zone 19N, NAD83(2011)). These UTM GRIDs were then transformed to geographic coordinates, using Global Mapper software, for

delivery. Geographic GRIDs were clipped to the deliverable tile extents with an additional 2-meter buffer applied to each tile.

Process Date/Time: 2012-12-01 00:00:00

Process Step 8

CC ID: 1133435

LIDAR FLIGHT LINE POLYGONS: Boundary polygons were created from the collected LiDAR swaths as ESRI shapefiles using a triangulation algorithm that produces an tight fitting outer boundary with concavities that accurately

represent the swaths as flown. The planned flight line number, swath file name and date of acquisition were then added as shapefile attributes.

Process Date/Time: 2012-12-01 00:00:00

Process Step 9

CC ID: 1133436

The NOAA Office for Coastal Management (OCM) received topographic files in LAS format. The files contained lidar

elevation and intensity measurements. The data were received in NAD83 Geographic Coordinates with units of decimal degrees.

The files were vertically referenced to NAVD88 using the Geoid12a model. The vertical units of the data were

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

1. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid12a.

Process Date/Time: 2013-01-01 00:00:00

Catalog Details

Catalog Item ID: 49609
GUID: gov.noaa.nmfs.inport:49609
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:21+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