Terrapoint USA20070528LAS_Metadata_CT_Dewberry.txtOneMapHouston, TexasTerrapoint USA
Project Area = 486 square kilometers
Type Of Scanner = Optech 3100EA
Data Acquisition Height = 1550 meters AGL
Scanner Field Of View = 46 degrees
Scan Frequency = 30.8 Hertz
Pulse Repetition Rate = 71 Kilohertz
Aircraft Speed = 150 Knots
Swath Width = 1316 m
Nominal Ground Sample Distance = 1.25 meters (no overlap)
Number of Returns Per Pulse = 4 (last)
Distance Between Flight Lines = 658m
www.terrapoint.comTerrapoint USA20070130Connecticut Coastline LiDAR SurveyHouston, TexasTerrapoint USAwww.terrapoint.comLAS_Metadata_CT_Dewberry.txt
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.
The purpose of this LiDAR data was to produce high accuracy
3D elevation based geospatial products for coastal flood
mapping.
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.
Water is included in the bare earth ground model, except
where the entire tile is covered by water.
en2006121620061218ground conditionNone planned-73.6677-71.825741.543140.9788NoneASPRS standardsDEMdigital elevation modelelevationLAS_v1.0laserLiDAROPTECH_3100EAsurface modeltopographyNoneFairfield CountyNew HavenMiddlesexNew LondonConnecticutNortheastUnited States
Dewberry & Davis LLC has full rights and ownership of this
LiDAR dataset; hence any data requests should be channeled
through Dewberry & Davis LLC.
Any conclusions from results of the analysis of this LiDAR
are not the responsibility of Terrapoint. The LiDAR data
was thoroughly visually verified to represent the true
ground conditions at time of collection. Users should be
aware of this limitations of this dataset if using for
critical applications.
DewberryDonald SyrianiProject Managermailing and physical address
8401 Arlington Boulevard
FairfaxVirginia22031USA1.703.849.03761.703.849.0648dsyriani@dewberry.comMonday to Friday, 8:30 - 4:30, Eastern TimeMicrosoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350Text File
Raw elevation measurements have been tested to 0.23 feet
vertical accuracy at 95 percent confidence level
All LiDAR files delivered were verified and tested to
ensure they open and are positioned properly.
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.
Compiled to meet 3 foot vertical accuracy at the 95 percent
confidence level
Connecticut LiDAR dataset tested .34ft vertical accuracy at 95% confidence level in open terrain, based on open terrain RMSEz (.17ft) x 1.9600; tested .43ft vertical accuracy at 95% confidence level in all land cover categories combined, based on consolidated RMSEz (.22ft) x 1.9600.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).Terrapoint USA20070528Connecticut Coastline LiDAR SurveyOnemapHouston, TexasTerrapoint USAwww.terrapoint.comTerrapoint USA20070130Connecticut Coastline LiDAR SurveyHouston, TexasTerrapoint USAwww.terrapoint.comHard Drive2006121620070228LiDAR data representing coastal Connecticut
- 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.
Acquisition200712ACQShiva ShenoyTerrapoint USAProduction Managermailing and physical address
251216 Grogan's Park Drive
The WoodlandsTexas77380USA1-877-80-TERRA1-281-296-0869shiva.shenoy@terrapoint.comMonday to Friday, 8:30 - 4:30, Eastern Time
- 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. Data
- 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.
Production200701-200702PRDClaude VickersTerrapoint USAProduction Managermailing and physical address
251216 Grogan's Park Drive
The WoodlandsTexas77380USA1-877-80-TERRA1-281-296-0869claude.vickers@terrapoint.com
Monday to Friday, 8:30 - 4:30, Eastern Time
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Metadata imported.20070914VectorGT-polygon composed of chains
17935
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State Plane Coordinate SystemConnecticut41.20000041.866667-72.75000040.833333999999.999894499999.999947Coordinate pair0.010.01US Survey FeetNorth American Datum of 1983GRS 8020925604.4720406298.26North American Vertical Datum of 19880.010.01
Explicit elevation coordinate included
with horizontal coordinates
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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
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Terrapoint USAClaude VickersProduction Managermailing and physical address
251216 Grogan's Park Drive
The WoodlandsTexas77380USA1-877-80-TERRA1-281-296-0869claude.vickers@terrapoint.comMonday to Friday, 8:30 - 4:30, Eastern Time
The LiDAR data was captured for Dewberry & Davis for
coastal flood mapping purposes
Users must assume responsibilty to determine the
appropriate use of this LiDAR dataset.
The LiDAR has been compiled to 3 foot vertical accuracy;
tested to 0.23 feet vertical accuracy at 95 percent
confidence level.
Data is representative of ground conditions at time of
acquisition only.
LAS1.0DVD, HDStandard
Current Handling and Processing Terrapoint Fees
Current Handling and Processing Terrapoint Fees
Current Terrapoint Handling and Processing Fees
Proper release required from Dewberry & Davis LLC for
orders outside of Dewberry & Davis LLC. Please contact
Terrapoint sales for general Terrapoint LiDAR library sales.
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20070914noneTerrapoint USAClaude VickersProduction ManagerMailing and physical address
251216 Grogan's Park Drive
The WoodlandsTexas77380USA1-877-80-TERRA1-281-296-0869claude.vickers@terrapoint.comMonday to Friday, 8:30 - 4:30, Eastern TimeFGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998enlocal timehttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile{0BD62E14-01F8-4F21-B523-2745F7678DE1}2007091408101200FALSE20070914084302002007091408430200Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350LAS_Metadata_CT_Dewberry.txtISO 19115 Geographic Information - MetadataDIS_ESRI1.0dataset002Text File20070914