49654
2006 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Connecticut Coastline Survey
ct2006_fema_coastal_m1468_metadata
Data Set
Published / External
49401
Lidar - partner (no harvest)
Project
Completed
2013-04
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.
The purpose of this LiDAR data was to produce high accuracy 3D elevation based geospatial products for coastal flood mapping.
10298
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
Theme
ISO 19115 Topic Category
elevation
Theme
ASPRS standards
Theme
OPTECH_3100EA
Office for Coastal Management
Charleston
SC
Data Set
As Needed
las
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
None
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.
Data Steward
2013-04
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Distributor
2013-04
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Metadata Contact
2013-04
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Point of Contact
2013-04
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Ground Condition
-73.659952
-71.829101
41.540542
40.979296
Range
2006-12-16
2006-12-18
Yes
Unclassified
This data can be obtained on-line at the following URL:
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1468
;
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.
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1468
Customized Download
Create custom data files by choosing data area, product type, map projection, file format, datum, etc.
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1468/index.html
Bulk Download
Simple download of data files.
https://coast.noaa.gov
Online Resource
https://coast.noaa.gov/dataviewer
Online Resource
2016-05-23
Date that the source FGDC record was last modified.
2017-11-14
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.
2018-02-08
Partial upload of Positional Accuracy fields only.
2018-03-13
Partial upload to move data access links to Distribution Info.
Raw elevation measurements have been tested to 0.23 feet vertical accuracy at 95 percent confidence level
Compiled to meet 1 meter horizontal accuracy at the 95 percent confidence level
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.
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.
All LiDAR files delivered were verified and tested to ensure they open and are positioned properly.
1
- 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.
2007-12-01T00:00:00
2
- 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.
2007-01-01T00:00:00
3
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.
2013-04-01T00:00:00
gov.noaa.nmfs.inport:49654
Anne Ball
2017-11-15T15:21:26
SysAdmin InPortAdmin
2022-08-09T17:11:37
2022-03-16
OCM Partners
OCMP
1002
Public
No
2022-03-16
1 Year
2023-03-16