During 2001 the NOAA Ship RUDE completed charting survey
H11044 that covered a roughly 293 km2 area of the sea floor in
north-central Long Island Sound, off Milford Connecticut. Although 100
percent coverage was achieved with sidescan sonar for charting
purposes, only reconnaissance (spaced line) bathymetry was acquired
with shallow-water multibeam and single-beam systems. Therefore,
further processing was conducted at the USGS's Woods Hole Science
Center to provide bathymetric datasets with more continuous coverage.
This project produced grids and GeoTIFF imagery of the combined and
interpolated shallow-water multibeam and single-beam bathymetry
generated from the northern part of this data set. Anthropogenic
wastes, toxic chemicals, and changes in land-use patterns resulting
from residential, commercial, and recreational development have
stressed the environment of the Sound, causing degradation and
potential loss of benthic habitats. Detailed maps of the sea floor are
needed to help evaluate the extent of adverse impacts and to help
manage resources wisely in the future. Therefore, in a continuing
effort to better understand Long Island Sound, we have interpolated and
gridded shallow-water multibeam and single-beam bathymetric data within
specific areas of special interest.
Purpose:
To release the ASCII file containing the 1.5-m
horizontally spaced bathymetry generated from NOAA survey H11044 in
north-central Long Island Sound off Milford, Connecticut. This file
contains the entire dataset, and not just the northern section covered
by the other datasets released as part of this project.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20010507
Ending_Date: 20011113
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -73.131256
East_Bounding_Coordinate: -72.936531
North_Bounding_Coordinate: 41.2463314
South_Bounding_Coordinate: 41.023193
Keywords:
Theme:
Theme_Keyword_Thesaurus: General
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Woods Hole Science Center
Theme_Keyword: multibeam bathymetry
Theme_Keyword: bathymetry
Theme_Keyword: Coastal and Marine Geology
Program
Theme_Keyword: CMGP
Theme_Keyword: WHSC
Theme_Keyword: NOAA survey H11044
Theme_Keyword: H11044
Theme_Keyword: National Oceanic and
Atmospheric Administration
Theme_Keyword: NOAA
Theme_Keyword: Reson 8125
Theme_Keyword: Open-File Report 2008-1146
Theme_Keyword: ASCII text
Theme_Keyword: OFR 2008-1146
Theme_Keyword: point grid
Theme_Keyword: single-beam bathymetry
Theme_Keyword: shallow-water multibeam
Theme_Keyword: Reson SeaBat 9003 echosounder
Theme_Keyword: Odom Echotrac DF-3200
echosounder
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic
Category
Theme_Keyword: oceans and estuaries
Theme_Keyword: oceans and coastal
Theme_Keyword: elevation
Theme_Keyword: oceans
Place:
Place_Keyword_Thesaurus: General
Place_Keyword: Connecticut
Place_Keyword: Milford
Place_Keyword: U.S. East Coast
Place_Keyword: United States
Place_Keyword: North America
Place_Keyword: Atlantic Ocean
Place_Keyword: Long Island Sound
Place_Keyword: Stratford Point
Place_Keyword: Charles Island
Access_Constraints: None
Use_Constraints:
Data are not to be used for navigation purposes.
Public domain data are freely redistributable with proper
metadata and source attribution. Please recognize the National Oceanic
and Atmospheric Administration (NOAA) as the originator of this
information.
All collected data from NOAA survey H11044 were processed and
used to produce this dataset.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Navigation was by differential GPS
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The vertical resolution of the shallow-water
multibeam data is approximately 0.5% of the water depth.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Type_of_Source_Media: DVD-ROM
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20010507
Ending_Date: 20011113
Source_Currentness_Reference: ground
condition
Source_Contribution:
The original processed shallow-water multibeam and
single-beam bathymetric data.
Process_Step:
Process_Description:
The multibeam data were acquired in XTF (extended
Triton data format) and recorded digitally through an ISIS data
acquisition system. A Reson SeaBat 9003 echosounder was used to acquire
the shallow-water multibeam bathymetric data and an Odom Echotrac
DF-3200 dual-frequency echosounder was used to acquire the single-beam
bathymetry from the NOAA ship Rude. An Odom Echotrac DF-3200
dual-frequency echosounder hull-mounted on a 23' launch deployed from
the NOAA ship Rude was used to acquire sounding data in the shallower
areas. These data were processed using CARIS HIPS (Hydrographic Image
Processing System) software for quality control, and to incorporate
sound velocity and tidal corrections. Sound velocity corrections were
derived using frequent SEACAT CTD (conductivity-temperature-depth)
profiles. Typically, a CTD cast was conducted every four to six hours
of multibeam acquisition. Tidal zone corrections were calculated from
data acquired at tidal gauges at Bridgeport and NewHaven, Connecticut,
and at Kings Point, New York. The vertical resolution of the
shallow-water multibeam data is approximately 0.5% of the water depth.
The data were gridded to 1.5-m resolution and exported in text (.txt)
format. Vertical datum is mean lower low water; X and Y units are
decimal degrees.
Depth_Encoding_Method: Explicit depth
coordinate included with horizontal coordinates
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
Three space separated values per record. Value one is
latitude in decimal degrees of the ship coordinate; value 2 is the
longitude in decimal degrees the ship's coordinate; value three is the
acquired depth value. The depth value is recorded in meters (to three
decimal places) as a positive value.
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological
Survey
Contact_Person: Larry Poppe
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical
address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: (508) 548-8700 x2314
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address:
lpoppe@usgs.gov
Resource_Description:
Downloadable Data (File size: Text version 2.74Gb, WinZipped
version 7.86 Mb)
Distribution_Liability:
Neither the U.S. Government, the Department of the Interior,
the USGS, NOAA, Connecticut Department of Environmental Protection, nor
any of their employees, contractors, or subcontractors, make any
warranty, express or implied, nor assume any legal liability or
responsibility for the accuracy, completeness, or usefulness of any
information, apparatus, product, or process disclosed, nor represent
that its use would not infringe on privately owned rights.
Any use of trade, product, or firm names is for descriptive purposes
only and does not imply endorsement by the U.S. Government.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ASCII
Format_Information_Content:
The ASCII data (h11044_1_5mddeg_xyz.txt), browse
graphic, and metadata. Caution: The downloadable files are large: text
version is 2.74 Gb, the WinZipped version is 786 Mb.