Bathymetric data of Long Island Sound developed from 1:100,000-scale NOAA bathymetry and USGS topographic-bathymetry maps. Depth units are meters.
The Long Island Sound Study developed these digital data from 1:100,000-scale National Oceanic & Atmospheric Administration (NOAA) and United States Geological Survey (USGS) maps as a general reference to the depth of water in Long Island Sound. In 1996, these data were digitized from paper maps by the Long Island Sound Study (http://www.longislandsoundstudy.net) and incorporated into a Long Island Sound GIS database. Not intended for maps printed at map scales greater or more detailed than 1:100,000 scale (1 inch = 1,578 feet.)
publication date
None. No restrictions or legal prerequisites for using the data after access is granted. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:100,000 scale (1 inch = 1.578 mile). Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge NOAA and the USGS as primary data sources.
Connecticut Department of Environmental Protection
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Long Island Sound Resource Center
University of Connecticut - Avery Point
Marine Science Building
1080 Shennecossett Road
Applied Geographics, Inc. of Boston, Massachussets was contracted by the Long Island Sound Study to automate and digitize these bathymetry data for Long Island Sound. Linda Bischoff, GIS GIS Analyst, digitized the data and created the orginal metadata.
All attributes have valid values. Values are within defined domains and valid ranges. The accuracy test for the DEPTH_M and DEPRESSION attribute values was conducted by comparing the information presented in the source data with check plots or interactive displays of the data on a computer graphic system. These tests were conduced by Applied Geographics, Inc. of Boston, Massachussets, which was contracted by the Long Island Sound Study to digitize bathymetry information from 1:100,000-scale NOAA bathymetry and USGS topographic-bathymetry maps.
Line features conform to the following topological rules. In general, lines are single part, and there are no duplicate lines. No tests of logical consistency were performed by the State of Connecticut using ESRI ArcInfo software to maintain feature topology in ArcInfo coverage format. Consequently, these data may not be topologically clean. Lines may self overlap and overlap other lines. Lines may not intersect only at nodes, which anchor the ends of all lines. Lines may overshoot or undershoot other lines they are supposed to meet and intersect.
The completeness of the data reflects the feature content of the data sources, whiich are published 1:100,000-scale NOAA bathymetry and USGS topographic-bathymetry maps. This data is not updated.
The horizontal positional accuracy of this data is unknown.
Bathymetry lines and depth values from two NOAA bathymetry and two USGS topographic-bathymetry maps. These data are based on National Ocean Service, NOAA/USGS, 1989, 1984, 1986, 1984 four adjacent sheets covering majority of Long Island Sound, but published at different times by NOS through different parent agencies.
Bathymtry data from four published maps covering Long Island Sound in ESRI ArcInfo Coverage format. Coordinate System is UTM Zone 18N, NAD27, map units meters.
Bathymtry data from four published maps covering Long Island Sound in ESRI Geodatabase Feature Class format. Coordinate system is Connecticut State Plane, NAD 83, map units feet.
Two bathy-topo sheets and two bathy-fishing maps automated partially through table digitizing and partially through scanning/vectorization of mylar separates. Data from these four bathy maps assembled into one ArcInfo coverage covering all of Long Island Sound.
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The 2007 edition is a modified version of the original data, which was projected to the Connecticut State Plane Coordinate System, North American Datum by the State of Connecticut, Department of Environmental Protection. CT DEP also modified attribute names and values to make them easier to understand and use. Using ESRI ArcGIS 9.1 software, the following modifications were made to the bathymetry data. 1. Using ArcInfo Workstation software, merged ArcInfo Coverage line features touching each other at end nodes to form fewer, longer line features with the Unsplit command. The Build command was subsequently used to restablish ArcInfo Coverage line feature topology. The Clean command was not used. Reduced number of features from 23,032 to 9,839. 2. Using ArcInfo Workstation software, projected the ArcInfo Coverage from UTM Zone 18N, NAD27 (map units meters) to the Connecticut State Plane Coordinate System, NAD83 (map units feet). 3. Using ArcGIS Desktop software, converted data format from ArcInfo Coverage to Geodatabase Feature Class. Spatial Reference Properties for new Feature Class: Coordinate System: NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet XY Domain MinX: 100000; MaxX: 2247483.645 XY Domain MinY: 200000; MaxY: 2347483.645 Precision: 1000 4. Attribute enhancements - The following attribute names and values were modified to make them easier to understand and use. The DEPTH attribute was renamed DEPTH_M to denote the units of measure (meters). The attributed named DEP was renamed DEPRESSION. Blank values in the DEPRESSION field were filled in with values of "N" (for no) to complement the"Y" values associated with all other features.
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Internal feature number.
ESRI
Water depth in meters.
USGS, NOAA
Indicates bathymetric line is a depression.
USGS, NOAA
Line is a depression. Catographically, these contours are normally symbolized with a hatch pattern.
USGS, NOAA
Line is regular bathmetric contour
USGS, NOAA
Feature geometry.
ESRI
Includes depth contour features. Use the DEPTH_M attribute to label line features with depth values. Use the DEPRESSION attribute to symbolize line features by type on a map.
not applicable
79 Elm Street
Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata.
The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.
University of Connecticut - Avery Point
Marine Sciences Building
1080 Shennecossett Road
79 Elm Street