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OCM Partners, 2022: 2006 Federal Emergency Management Agency (FEMA) Topographic Lidar: Bristol and Plymouth Counties, Massachusetts,

Item Identification

Title: 2006 Federal Emergency Management Agency (FEMA) Topographic Lidar: Bristol and Plymouth Counties, Massachusetts
Short Name: ma2006_fema_bristolplymouth_m2602_metadata
Status: Completed
Publication Date: 2013-11

FEMA Contract No. EME-2003-CO-0340

FEMA Task Order T018

Sanborn Map Company furnished the collection and processing, and development of Lidar and contours using photogrammetry to support the FEMA mapping

requirements for a total of 142 square miles in coastal areas in Plymouth and Bristol Counties in Massachusetts. The 142 square miles includes the

communities of Westport, Dartmouth, New Bedford, Fairhaven, Mattapoisett, Marion, and Wareham. The project area was defined using a buffered shapefile

with limits along the coastline. The project area included a portion of both counties. All lidar data was acquired during November 2006 by Sanborn.

Orthophotography used to create 2D breaklines was produced in 2005 by MassGIS as part of its statewide orthophoto program. All lidar data that

was acquired was produced in accordance with FEMA specifications (Source: FEMA Guidelines and Specifications, Appendix N, Section N.1.2).

Lidar Acquisition Parametes:

Average Altitude: 1,200 Meters AGL

Airspeed: ~120 Knots

Scan Frequency: 36 Hertz

Scan Width Half Angle: 16 Degrees

Pulse Rate: 50000 Hertz

The data being distributed through the NOAA Digital Coast are Gridded Bare-Earth LAS files.


The LIDAR derived data sets, including the first and last returns, a Gridded DEM, TIN file, 2' contours in ESRI geodatbase format and masspoint and

Breakline files were developed to support Camp Dresser and McKee's continued development of updated Digital Flood Insurance Rate Maps and flood

insurance studies for coastal areas in Massachusetts. Contours are based on bare earth LIDAR and breaklines digitized from 2D orthophotography

(subsequently draped over the 3D LIDAR points) (Source: FEMA Guidelines and Specs, Appendix N). Coastal shoreline areas were set a 0.00 elevation to

cartographically represent contours.



Supplemental Information:

A complete description of this dataset is available in the project report submitted to FEMA Region 1 by CDM:

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


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
FEMA NFIP Topic Category Breaklines
FEMA NFIP Topic Category Contours
FEMA NFIP Topic Category DEM
FEMA NFIP Topic Category Digital Terrain Model
FEMA NFIP Topic Category Elevation Data
FEMA NFIP Topic Category Flow vectors
FEMA NFIP Topic Category Land Surface
FEMA NFIP Topic Category LIDAR
FEMA NFIP Topic Category Relief
FEMA NFIP Topic Category Slope
FEMA NFIP Topic Category Topography

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
Entity Attribute Overview:

LiDAR points in LAZ format (ASPRS Class 2,7)

Entity Attribute Detail Citation:


Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of FEMA, Sanborn, CDM, MASSGIS, NOAA, the Office for Coastal Management

or its partners.

Support Roles

Data Steward

CC ID: 676321
Date Effective From: 2013-11
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: 676323
Date Effective From: 2013-11
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: 676324
Date Effective From: 2013-11
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: 676322
Date Effective From: 2013-11
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: 1134958
W° Bound: -71.136354
E° Bound: -70.588933
N° Bound: 41.795113
S° Bound: 41.47402

Extent Group 1 / Time Frame 1

CC ID: 1134957
Time Frame Type: Range
Start: 2006-11-10
End: 2006-11-26

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: 741246
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: 741247
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 741249
URL Type:
Online Resource


CC ID: 741250
URL Type:
Online Resource


CC ID: 741251
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the lidar coverage for the communities of Westport, Dartmouth, New Bedford, Fairhaven, Mattapoisett, Marion, and Wareham.

Activity Log

Activity Log 1

CC ID: 676345
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 676344
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: 718337
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 741248
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality

Vertical Positional Accuracy:

The lidar data was evaluated using a collection of 11 GPS surveyed checkpoints. The category classes of bare earth, low grass and urban were used.

For the Bristol checkpoints, the RMSEz is 14.7 centimeters. This area yielded much better results than the project requirement of 18.5 centimeters

RMSEz. The vertial accuracy of the source data meet or exceed vertical National Map Accuracy Standards for 2-foot contour mapping. Please set the

Project Report located in the supplemental information section above for more details.

; Quantitative Value: 0.294 meters, Test that produced the value:

This value reflects the data's tested Vertical Root Mean Squared Error (RMSEz) at 95% confidence interval (RMSEz @ 95% confidence = RMSEz x 1.9600)

as defined by the Federal NSSDA (National Spatial Standard for Data Accuracy). Units in meters.

Completeness Report:

Terrain data are derived datasets that aid automated hydrologic and hydraulic analyses, the flood hazard area boundary delineations, and quality control.

Conceptual Consistency:

Sanborn used proprietary algorithms to remove features and artifacts in the first and last return data that did not reflect true ground elevations. New

aerial stereo photography was flown, and aerial triangulated to allow production of breakline ehnacement of the Bare earth DEM and to hydrologically

enforce contours and elevation data through the compilation of drainage breaklines.


Process Steps

Process Step 1

CC ID: 1134954

Using an Optech Light Detection and Ranging (LiDAR) system, flight lines were planned for standard density 1.4 meter GSD. The Flight plan for the

project includes the following specifications to fully meet the project requirements - single pass density of approximately 2.0 square meters per

sample * Swath width 728 meters * Flight altitude 1000 meters * flight line spacing -589 meters with 125 meters overlap *Scan Frequency- 35 Hz *Scan

Angle- 20 degrees * Aircraft ground speed -- 140 knots * System Calibration pre and post mission * Two GPS base stations within 30 KM. Multiple

returns were recorded for each laser pulse along with an intensity value for each return. The data are calibrated for geographic referencing. Points

are further processed, using TerraSolid software, to classify return values. The first and last return data is filtered to remove the vegetation

and above ground manmade features to yield a ground surface. The bare earth elevation data was draped over the existing orthophotos. Breaklines

for hydrographic features, bridges, culverts and major roadways were captured in 2D. Elevations were associated to the breaklines by draping onto

the Lidar data. The DTM was then used to produce a TIN. The TIN was used to generate 2-ft contours.

Process Date/Time: 2006-12-31 00:00:00

Process Step 2

CC ID: 1134955

The NOAA Office for Coastal Management (OCM) received topographic files in ASCII format. The files contained lidar elevation measurements. The data

were received in Massachusetts State Plane Mainland (Zone 2001), NAD83 coordinates and were vertically referenced to NAVD88 using the Geoid03

model. The vertical units of the data were feet. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The ASCII files were converted to LAS V1.2 using LASTools' txt2las.

2. The topographic las file '8002645' was found to be corrupt and removed from the data set.

3. All points in the topographic las files were converted to Class 2 (Ground) using LASTools' las2las.

4. The topographic las files were found to contain noise, those points were manually reclassified to Class 7 (Noise) using Merrick MARS7.

5. All additional VLRs in the topographic las files' header used by MARS7 were removed using LASTools' las2las.

6. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid03.

7. The topographic las files were converted from a Projected Coordinate System (MA SP 2001) to a Geographic Coordinate System (NAD83).

8. The topographic las files' horizontal units were converted from feet to decimal degrees.

9. The topographic las files' vertical units were converted from feet to meters.

Process Date/Time: 2013-11-01 00:00:00

Catalog Details

Catalog Item ID: 49770
GUID: gov.noaa.nmfs.inport:49770
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