2006 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Connecticut Coastline Survey
Data Set (DS) | OCM Partners (OCMP)GUID: gov.noaa.nmfs.inport:49654 | Updated: August 9, 2022 | Published / External
Summary
Short Citation
OCM Partners, 2025: 2006 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Connecticut Coastline Survey, https://www.fisheries.noaa.gov/inport/item/49654.
Full Citation Examples
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 was planned for a 50% acquisition overlap. The nominal resolution of this project
without overlap is 1.25m. 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 v1.0 format, classified according to ASPRS Class Code 2=Ground 1=Undefined. Water is included
in the bare earth ground model, except where the entire tile is covered by water.
The following regions of Connecticut are included in this project:
Fairfield County - 130 square kilometers
New Haven - 170 square kilometers
Middlesex - 29 square kilometers
New London - 157 square kilometers
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.
Distribution Information
-
Create custom data files by choosing data area, product type, map projection, file format, datum, etc.
-
Simple download of data files.
None
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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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.
Controlled Theme Keywords
elevation
Child Items
No Child Items for this record.
Contact Information
Point of Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov
Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov
Extents
-73.659952° W,
-71.829101° E,
41.540542° N,
40.979296° S
2006-12-16 - 2006-12-18
Item Identification
Title: | 2006 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Connecticut Coastline Survey |
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Short Name: | ct2006_fema_coastal_m1468_metadata |
Status: | Completed |
Publication Date: | 2013-04 |
Abstract: |
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 was planned for a 50% acquisition overlap. The nominal resolution of this project without overlap is 1.25m. 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 v1.0 format, classified according to ASPRS Class Code 2=Ground 1=Undefined. Water is included in the bare earth ground model, except where the entire tile is covered by water. The following regions of Connecticut are included in this project: Fairfield County - 130 square kilometers New Haven - 170 square kilometers Middlesex - 29 square kilometers New London - 157 square kilometers 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. |
Purpose: |
The purpose of this LiDAR data was to produce high accuracy 3D elevation based geospatial products for coastal flood mapping. |
Notes: |
10298 |
Supplemental Information: |
A footprint of this data set may be viewed in Google Earth at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1468/supplemental/ct2006_fema_coastal_footprint.KMZ A field survey report is available at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1468/supplemental/ct2006_fema_coastal_fieldsurveyreport.pdf A QA/QC report is available at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1468/supplemental/ct2006_fema_coastal_qaqcreport.pdf |
Keywords
Theme Keywords
Thesaurus | Keyword |
---|---|
ISO 19115 Topic Category |
elevation
|
UNCONTROLLED | |
None | ASPRS standards |
None | OPTECH_3100EA |
Physical Location
Organization: | Office for Coastal Management |
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City: | Charleston |
State/Province: | SC |
Data Set Information
Data Set Scope Code: | Data Set |
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Maintenance Frequency: | As Needed |
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: |
None |
Distribution Liability: |
Any conclusions drawn from the analysis of this information are not the responsibility of Dewberry & Davis LLC, Terrapoint USA, FEMA, NOAA, the Office for Coastal Management or its partners. |
Support Roles
Data Steward
Date Effective From: | 2013-04 |
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Date Effective To: | |
Contact (Organization): | NOAA Office for Coastal Management (NOAA/OCM) |
Address: |
2234 South Hobson Ave Charleston, SC 29405-2413 |
Email Address: | coastal.info@noaa.gov |
Phone: | (843) 740-1202 |
URL: | https://coast.noaa.gov |
Distributor
Date Effective From: | 2013-04 |
---|---|
Date Effective To: | |
Contact (Organization): | NOAA Office for Coastal Management (NOAA/OCM) |
Address: |
2234 South Hobson Ave Charleston, SC 29405-2413 |
Email Address: | coastal.info@noaa.gov |
Phone: | (843) 740-1202 |
URL: | https://coast.noaa.gov |
Metadata Contact
Date Effective From: | 2013-04 |
---|---|
Date Effective To: | |
Contact (Organization): | NOAA Office for Coastal Management (NOAA/OCM) |
Address: |
2234 South Hobson Ave Charleston, SC 29405-2413 |
Email Address: | coastal.info@noaa.gov |
Phone: | (843) 740-1202 |
URL: | https://coast.noaa.gov |
Point of Contact
Date Effective From: | 2013-04 |
---|---|
Date Effective To: | |
Contact (Organization): | NOAA Office for Coastal Management (NOAA/OCM) |
Address: |
2234 South Hobson Ave Charleston, SC 29405-2413 |
Email Address: | coastal.info@noaa.gov |
Phone: | (843) 740-1202 |
URL: | https://coast.noaa.gov |
Extents
Currentness Reference: | Ground Condition |
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Extent Group 1
Extent Group 1 / Geographic Area 1
W° Bound: | -73.659952 | |
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E° Bound: | -71.829101 | |
N° Bound: | 41.540542 | |
S° Bound: | 40.979296 |
Extent Group 1 / Time Frame 1
Time Frame Type: | Range |
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Start: | 2006-12-16 |
End: | 2006-12-18 |
Spatial Information
Spatial Representation
Representations Used
Vector: | Yes |
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Access Information
Security Class: | Unclassified |
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Data Access Procedure: |
This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1468 ; |
Data Access Constraints: |
None |
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
Download URL: | https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1468 |
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Distributor: | |
File Name: | Customized Download |
Description: |
Create custom data files by choosing data area, product type, map projection, file format, datum, etc. |
Distribution 2
Download URL: | https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1468/index.html |
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Distributor: | |
File Name: | Bulk Download |
Description: |
Simple download of data files. |
URLs
URL 1
URL: | https://coast.noaa.gov/dataviewer |
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URL Type: |
Online Resource
|
URL 2
URL: | https://coast.noaa.gov |
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URL Type: |
Online Resource
|
Activity Log
Activity Log 1
Activity Date/Time: | 2016-05-23 |
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Description: |
Date that the source FGDC record was last modified. |
Activity Log 2
Activity Date/Time: | 2017-11-14 |
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Description: |
Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details. |
Activity Log 3
Activity Date/Time: | 2018-02-08 |
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Description: |
Partial upload of Positional Accuracy fields only. |
Activity Log 4
Activity Date/Time: | 2018-03-13 |
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Description: |
Partial upload to move data access links to Distribution Info. |
Data Quality
Accuracy: |
Raw elevation measurements have been tested to 0.23 feet vertical accuracy at 95 percent confidence level |
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Horizontal Positional Accuracy: |
Compiled to meet 1 meter horizontal accuracy at the 95 percent confidence level |
Vertical Positional Accuracy: |
Independent accuracy testing was performed by Dewberry & Davis using 80 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 (NDEP), and American Society for Photogrammetry and Remote Sensing (ASPRS). ; Quantitative Value: 0.10 meters, Test that produced the value: Value in meters. Connecticut LiDAR dataset tested 0.10m(.34ft) vertical accuracy at 95% confidence level in open terrain, based on open terrain RMSEz (.17ft) x 1.9600; tested 0.13m (.43ft) vertical accuracy at 95% confidence level in all land cover categories combined, based on consolidated RMSEz (.22ft) x 1.9600. |
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. |
Lineage
Process Steps
Process Step 1
Description: |
- General Overview The Airborne LiDAR survey was conducted using an OPTECH 3100EA flying at a nominal height of 1550 metres AGL with a total angular coverage of 40 degrees. Flight line spacing was nominally 564 metres 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 metres 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. 72 flight lines were flown over the Connecticut Coastline site to provide complete coverage. |
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Process Date/Time: | 2007-12-01 00:00:00 |
Process Step 2
Description: |
- 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 1407 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 Connecticut State Plane final projection system and US survey feet using an in-house transformation software which uses the Coorpscon DLL. |
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Process Date/Time: | 2007-01-01 00:00:00 |
Process Step 3
Description: |
The NOAA Office for Coastal Management (OCM) received the topographic files in LAZ V1.0 format. The files contained lidar elevation measurements. The data were received in Connecticut State Plane coordinates, NAD83 (Zone 0600) 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 topographic las files were converted from a Projected Coordinate System (Connecticut SP 0600) to a Geographic Coordinate system (NAD83). 2. The topographic las files' horizontal units were converted from US survey feet to decimal degrees. 3. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid03. 4. The topographic las files' vertical units were converted from survey feet to meters. |
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Process Date/Time: | 2013-04-01 00:00:00 |
Catalog Details
Catalog Item ID: | 49654 |
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GUID: | gov.noaa.nmfs.inport:49654 |
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 |