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OCM Partners, 2024: 2012 USACE Post Sandy Topographic LiDAR: Coastal Connecticut,

Item Identification

Title: 2012 USACE Post Sandy Topographic LiDAR: Coastal Connecticut
Short Name: 2012_USACE_PostSandy_Connecticut_m1434_metadata
Status: Completed
Publication Date: 2013-01

This data has been acquired and developed by the U.S. Corps of Engineers ST. Louis District to collect and deliver topographic elevation point data derived from multiple return light detection and ranging (LiDAR)

measurements for the 116 sq. mile project area encompassing the entire coastal region of the State of Connecticut. Fugro EarthData, Inc. acquired 46 flight lines in 4 lifts from November 14, 2012 to December 16, 2012.

LiDAR data collection was performed with a Cessna 310 twin engine aircraft, utilizing a Leica ALS60 MPiA sensor; collecting multiple return x, y, and z as well as intensity data. The classified LiDAR point cloud data are

delivered in LAS 1.2 format: 1 unclassified, 2 ground, 7 low points, 8 model keypoints, 9 water, and 10 ignored points. Specialized in-house and commercial software processes the native LiDAR data into 3-dimensional

positions that can be imported into GIS software for visualization and further analysis.

Original contact information:

Contact Org: USACE, St. Louis District

Phone: 314-331-8389



To acquire, process and store multiple-return LiDAR calibrated and classified point cloud data using compliant LAS 1.2 format with the following collection conditions: Atmospheric: cloud and fog free between aircraft

and ground; Ground Vegetation: leaf off preferred; Flight Height: as required to acquire point data sufficient to meet requirements. Additionally the LiDAR data must collected at or below MLW tidal elevation 0 whenever possible.



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
Entity Attribute Overview:

Leica ALS60 MPiA sensor; 1.0m nominal post spacing

Entity Attribute Detail Citation:

see process steps within this record

Distribution Liability:

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

of Fugro Earth Data, USACE, USGS, NOAA, the Office for Coastal Management or its partners.

Data Set Credit: USACE, St. Louis District

Support Roles

Data Steward

CC ID: 669647
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: 669649
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: 669650
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: 669648
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: 1133422
W° Bound: -73.661202
E° Bound: -71.847828
N° Bound: 41.396254
S° Bound: 40.951486

Extent Group 1 / Time Frame 1

CC ID: 1133421
Time Frame Type: Range
Start: 2012-11-14
End: 2012-11-16

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: 740301
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: 740302
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 740304
URL Type:
Online Resource


CC ID: 740305
URL Type:
Online Resource


CC ID: 740306
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: 669663
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 669662
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: 718048
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 740303
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Technical Environment


Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog

Data Quality


During LiDAR data collection the airborne GPS receiver was collecting data at 2 Hz frequency and the Dilution of Precision (PDOP) was monitored. One GPS base station was also running at the operation airport and was recording

data at 1 Hz. The airborne GPS data was post-processed in DGPS mode together with the base station data to provide high accuracy aircraft positions. The GPS trajectory then was combined with the IMU data using loosely coupled

approach to yield high accuracy aircraft positions and attitude angles. Then the LiDAR data was processed using the aircraft trajectory and raw LiDAR data. After boresighting the LiDAR data, the ground control points were

measured against the LiDAR data by technicians using TerraScan and proprietary software and the LiDAR data was adjusted vertically to the ground control. Independent ground control check points were used to ensure vertical

accuracy of the data. The horizontal datum for the data is geographic Coordinates, NAD83(NA2011) in meters and the vertical datum is the North American Vertical Datum of 1988 (NAVD88) in meters. The vertical datum was

realized through the use of the published/calculated ellipsoidal heights of the base station to process the aircraft trajectory and then later applying the GEOID12A model to the processed LiDAR data to obtain orthometric heights.

Horizontal Positional Accuracy:

The minimum expected horizontal accuracy was tested to meet or exceed the National Mapping Accuracy Standard (NMAS 1=100).

Vertical Positional Accuracy:

Accuracyz = RMSEz X 1.9600 at the 95% confidence level. However the RMSE is only valid when the errors follow a normal distribution which may not always be the case with LiDAR data particularly in vegetated land cover categories.

Therefore the data will also be tested using the ASPRS/NDEP method which acknowledges that vegetated land cover may not follow a normal error distribution. The ASPRS/NDEP methods mandate the use of Fundamental Vertical Accuracy

(FVA) in open terrain and provides for the optional use of Supplemental Vertical Accuracy (SVA) in other individual land cover categories and Consolidated Vertical Accuracy (CVA) in all land cover categories combined. FVA is

calculated at the 95th percent confidence level as a function of RMSEz. SVA and CVA are calculated at the 95th percentile, where 95% of elevations errors have elevation errors equal to or less that the 95th percentile.

; Quantitative Value: 0.05 meters, Test that produced the value: RMSE in meters

Completeness Measure:

Cloud Cover: 0

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

3) Measurement of quality control ground survey points within the finished product.

The following software is used for the validation: 1) Terrascan and 2) Fugro EarthData Proprietary Software.

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 performing a full boresight adjustment and then checking it against the ground control prior to generating a digital terrain model (DTM) or other products.

2) LiDAR elevation data was validated through an inspection of edge matching and visual inspection for quality (artifact removal).



Aerial Acquisition of Coastal Connecticut Sandy Response LiDAR

CC ID: 1133414
Publish Date: 2011-08-04
Extent Type: Range
Extent Start Date/Time: 2012-11-14
Extent End Date/Time: 2012-11-16
Source Contribution:

Fugro EarthData, Inc. collected ALS60-derived LiDAR over the project area with a 1.0 meter, nominal post spacing using a Cessna 310 twin engine aircraft. The collection for the entire project area was accomplished between

November 14, 2012 and November 16, 2012; 46 flight lines were acquired in 4 lifts. The lines were flown at an average of 1825 meters feet above mean terrain using a pulse rate of 123,700 pulses per second. The collection

was performed using Leica ALS60 MPiA LiDAR systems, serial number 142.

| Type of Source Media: External hard drive

Report of Control Survey Connecticut Coast Sandy Response

CC ID: 1133415
Publish Date: 2012-12-15
Extent Type: Range
Extent Start Date/Time: 2012-11-09
Extent End Date/Time: 2012-11-30
Source Contribution:

TerraSurv, Inc.under contract to Fugro EarthData, Inc. successfully established ground control for the Project. A total of 11 ground control points and 60 QC check points in 3 land classes were acquired. GPS was used to

establish the control network. The horizontal datum for the data is geographic Coordinates, NAD83(NA2011) in meters and the vertical datum is the North American Vertical Datum of 1988 (NAVD88) in meters using GEIOD12A.

| Type of Source Media: electronic mail system

Process Steps

Process Step 1

CC ID: 1133416

All acquired LiDAR data went through a preliminary review to assure that complete coverage was obtained and that there were no gaps between flight lines before the flight crew left the project site. Once back in the office,

the data is run through a complete iteration of processing to ensure that it is complete, uncorrupted, and that the entire project area has been covered without gaps between flight lines. There are essentially three steps to

this processing:

1) GPS/IMU Processing - Airborne GPS and IMU data was immediately processed using the airport GPS base station data, which was available to the flight crew upon landing the plane. This ensured the integrity of

all the mission data. These results were also used to perform the initial LiDAR system calibration test.

2) Raw LiDAR Data Processing - Technicians processed the raw data to LAS format flight lines with full resolution output

before performing QC. A starting configuration file was used in this process, which contains the latest calibration parameters for the sensor. The technician also generated flight line trajectories for each of the flight lines

during this process.

3) Verification of Coverage and Data Quality - Technicians checked flight line trajectory files to ensure completeness of acquisition for project flight lines, calibration lines, and cross flight lines.

The intensity images were generated for the entire lift at the required post spacing for the project. The technician visually checked the intensity images against the project boundary to ensure full coverage.

The intensity histogram was analyzed to ensure the quality of the intensity values. The technician also thoroughly reviewed the data for any gaps in project area. The technician generated a few sample TIN surfaces

to ensure no anomalies were present in the data. Turbulence was inspected for and if it affected the quality of the data, the flight line was rejected and reflown. The technician also evaluated the achieved post

spacing against project specified post spacing.

Process Date/Time: 2012-11-18 00:00:00

Process Step 2

CC ID: 1133417

The boresight for each lift was done individually as the solution may change slightly from lift to lift. The following steps describe the Raw Data Processing and Boresight process:

1) Technician processed the raw data to LAS format flight lines using the final GPS/IMU solution. This LAS data set was used as source data for boresight.

2) Technician first used commercial software to calculate initial boresight adjustment angles based on sample areas selected in the lift- mini project. These areas cover calibration flight lines collected in the lift,

cross tie and production flight lines. These areas are well distributed in the lift coverage and cover multiple terrain types that are necessary for boresight angle calculation. The technician then analyzed the result

and made any necessary additional adjustment until it is acceptable for the mini project.

3) Once the boresight angle calculation was done for the mini project, the adjusted settings were applied to all of the flight lines of the lift and checked for consistency. The technician utilized commercial and proprietary

software packages to analyze the matching between flight line overlaps for the entire lift and adjusted as necessary until the results met the project specifications.

4) Once the boresight adjustment was completed for each lift individually, the technician ran a routine to check the vertical misalignment of all flight lines in the project and also compared data to ground truth. The entire

dataset was then adjusted to ground control points.

5) The technician ran a final vertical accuracy check between the adjusted data and surveyed ground control points after the z correction. The result was analyzed against the project specified accuracy to make sure it meets

the project requirements

Process Date/Time: 2012-11-19 00:00:00

Process Step 3

CC ID: 1133418

Once boresighting is complete for the project, the project was set up for classification. The LiDAR data was cut to production tiles. The flight line overlap points, Noise points and Ground points were classified automatically

in this process. Fugro EarthData, Inc. has developed a unique method for processing LiDAR data to identify and re-classify elevation points falling on vegetation, building, and other above ground structures into separate data

layers. The steps are as follows:

1) Fugro EarthData, Inc. utilized commercial software as well as proprietary software for automatic filtering. The parameters used in the process were customized for each terrain type to obtain optimum results.

2) The Automated Process typically re-classifies 90-98% of points falling on vegetation depending on terrain type. Once the automated filtering was completed, the files were run through a visual inspection to ensure that the

filtering was not too aggressive or not aggressive enough. In cases where the filtering was too aggressive and important terrain features were filtered out, the data was either run through a different filter or was corrected

during the manual filtering process.

3) Interactive editing was completed in 3D visualization software which also provides manual and automatic point classification tools. Fugro EarthData, Inc. used commercial and proprietary software for this process. Vegetation

and artifacts remaining after automatic data post-processing were reclassified manually through interactive editing. The hard edges of ground features that were automatically filtered out during the automatic filtering

process were brought back into ground class during manual editing. Auto-filtering routines were utilized as much as possible within fenced areas during interactive editing for efficiency. The technician reviewed the LiDAR

points with color shaded TINs for anomalies in ground class during interactive filtering.

4) All LAS tiles went through peer review after the first round of interactive editing was finished. This helps to catch misclassification that may have been missed by the interactive editing.

5) Upon the completion of peer review and finalization of bare earth filtering, the classified LiDAR point cloud work tiles went through a water classification routine based on the collected water polygons.

6) The time stamps for all points were converted to Adjusted Standard GPS time using proprietary software developed by Fugro EarthData, Inc. The data collection date and the current GPS time stamp were used in calculating the

Adjusted Standard GPS time.

7) The classified point cloud data were packaged into geographic Coordinates, NAD83(NA2011) in meters and the vertical datum is the North American Vertical Datum of 1988 (NAVD88) in meters using GEIOD09 for delivery. The data

was also cut to the approved tile layout and clipped to the approved project boundary. The technician checked the output LAS files for coverage and format; d) the technician then QCd the dataset for quality assurance and

enhanced the Bare Earth classification in the project area for consistent data quality; ie) these final LiDAR tiles were then used in the hydro flattening process.

8) classified LiDAR point cloud data are delivered in LAS 1.2 format: 1 unclassified, 2 ground, 7 low points, 8 model keypoints, 9 water, and 10 ignored points.

Process Date/Time: 2012-11-27 00:00:00

Process Step 4

CC ID: 1133419

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 Geographic (NAD83) coordinates

and 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: 49607
GUID: gov.noaa.nmfs.inport:49607
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