Current Bathymetry Contours of Rhode Island

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: NOAA Coastal Services Center

Publication_Date: 20010731

Title: Current Bathymetry Contours of Rhode Island

Edition: One

Geospatial_Data_Presentation_Form: Map

Publication_Information:

Publication_Place: Charleston, South Carolina, USA

Publisher: NOAA Coastal Services Center

Other_Citation_Details:

This data layer was created from the Geophysical Data System (GEODAS) data sets compiled by the National Geophysical Data Center (NGDC) from NOAA hydrographic surveys.

Larger_Work_Citation:

Citation_Information:

Originator: NOAA Coastal Services Center

Publication_Date: 20010630

Title: Rhode Island Habitat Restoration Portal

Publication_Information:

Publication_Place: Charleston, South Carolina, USA

Publisher: NOAA Coastal Services Center

Online_Linkage: <http://www.csc.noaa.gov/lcr/rhodeisland>

Description:

Abstract:

The Bathymetry Contours of Rhode Island was created for use in the Rhode Island Habitat Restoration Portal project. Hydrographic survey data were imported into Environmental Systems Research Institute (ESRI), Inc., ArcView geographic information system (GIS) software for visualization. These data represent a composite of the bathymetric information gathered through the National Ocean Service hydrographic survey from Rhode Island waters from 1934 to 1996.

Purpose:

The data were created to represent a vector representation of a raster-based bathymetry surface that can be overlaid with other data to determine potential seagrass restoration sites.

Supplemental_Information:

Contours were generated from a grid surface. Grid creation involved mathematical interpolation of values for some cells in the data layer. These cell values were calculated through the creation of a Triangulated Irregular Network (TIN) and a GRID using the methods described in this document. Therefore, this represents an estimate of the actual bathymetry of Rhode Island waters. It is the user's responsibility to determine the appropriate application of this data layer.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1934

Ending_Date: 1996

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -71.9002

East_Bounding_Coordinate: -71.0950

North_Bounding_Coordinate: 41.8738

South_Bounding_Coordinate: 41.1154

Keywords:

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: Bathymetry

Theme_Keyword: Bathymetric data

Theme_Keyword: Depth

Theme_Keyword: Geographic Information Systems

Theme_Keyword: GIS

Theme_Keyword: Grid

Theme_Keyword: Contour

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: Rhode Island

Place_Keyword: Narragansett Bay

Place_Keyword: Rhode Island Sound

Place_Keyword: New England

Place_Keyword: Northeast

Access_Constraints: None

Use_Constraints:

It is the user's responsibility to determine the appropriate use of this data layer. The user should make a special note of contours that appear near the edge of the spatial extent as the generation of these edge data from points, tins and grids are inherently erroneous.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NOAA Coastal Services Center

Contact_Position:

Landscape Characterization and Restoration (LCR) Program Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: USA

Contact_Voice_Telephone: 843-740-1200

Contact_Facsimile_Telephone: 843-740-1224

Contact_Electronic_Mail_Address: csc@csc.noaa.gov

Hours_of_Service: Monday-Friday, 8am-5pm, Eastern Standard Time

Native_Data_Set_Environment:

ESRI Grid format i:\lcr\rhode_island\web_prototype\gis\shpfiles\contour

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

No formal tests were performed. The accuracy follows the data accuracy of the Geophysical Data System for Hydrographic Survey (GEODAS).

Logical_Consistency_Report:

The data were compared to Rhode Island state land boundary data and found to exist within state waters.

Completeness_Report:

These data are believed to be complete within the area of interest. In cases where multiple soundings occurred within 50 meters, older soundings were discarded. The remaining data available from 1934-1996 surveys were included in layer creation.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The accuracy follows the data accuracy of the Geophysical Data System for Hydrographic Survey (GEODAS). The data were retrieved from the GEODAS database with latitude/longitude coordinates in decimal degrees referenced to either the North American Datum of 1927 (NAD 27) or 1983 (NAD 83). All data points referenced to NAD 27 were then converted into NAD 83 using ArcView's Projection Utility Wizard extension and projected into Rhode Island State Plane Feet.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The data were referenced to local datum of mean low water (MLW) or mean lower low water (MLLW) at the time of collection, regardless of collection year, depending on the survey.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator:

NOAA National Environmental Satellite, Data, and Information Service (NESDIS)

Publication_Date: 1998

Title: Geophysical Data System (GEODAS) for Hydrographic Survey Data

Edition: Volume 1, Version 4.0

Geospatial_Data_Presentation_Form: tabular digital data

Publication_Information:

Publication_Place: Boulder, Colorado

Publisher:

NOAA National Geophysical Data Centers (NGDC), Marine Geology and Geophysics Division

Online_Linkage: <http://www.ngdc.noaa.gov/mgg/>

Type_of_Source_Media: CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1934

Ending_Date: 1996

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: NGDC

Source_Contribution:

The GEODAS CD-ROM contained the data and retrieval software needed to create this data layer.

Process_Step:

Process_Description:

The data were retrieved from the CD-ROM using the default HYD93 download and tabulated with header information. Data referenced to NAD 27 was separated from data referenced to NAD 83. The data were saved as DBF files and brought into ArcView as event themes. NAD 27 data were then converted from NAD 27 to NAD 83 using ArcView's Projection Utility Wizard extension and saved as a shapefile. All data were projected into Rhode Island State Plane (feet) and then merged using ArcView's Geoprocessing Wizard Utility.

Source_Used_Citation_Abbreviation: NGDC

Process_Date: 20010321

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NOAA Coastal Services Center

Contact_Position:

Landscape Characterization and Restoration Program (LCR) Program Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: USA

Contact_Voice_Telephone: 843-740-1200

Contact_Facsimile_Telephone: 843-740-1224

Contact_Electronic_Mail_Address: csc@csc.noaa.gov

Hours_of_Service: Monday-Friday, 8am-5pm, Eastern Standard Time

Process_Step:

Process_Description:

CREATING A TIN The shapefile was exported into a coverage using ArcCatalog. The point coverage was converted to a TIN using ArcToolbox using the "Create a tin" wizard with the following constraints: A hardclip area, using a hull approximately the size of the bathymetric point footprint confined the processing area. Weed tolerance was set to 200; z-value = 1. The hull (footprint) was created by taking the ribay.shp file (<http://www.edc.uri.edu/rigis-spf/statewide/state.html#boundaries>) and stretching four of the southernmost vertices to contain all of the bathymetric points. This shapefile was then exported to a coverage in ArcInfo workstation using the SHAPEARC command (default options) and then building for polygons. "Hard erase" areas were created from boundaries available from the above Web site (statline.shp). The land area was created from the statline.shp file by converting that file to a coverage in ArcCatalog. The islands were created by taking the ribay.shp file and selecting all the polygons that were not equal to water, converting that subset to a shapefile in ArcView, exporting that new shapefile to a coverage in workstation ArcInfo using the SHAPEARC command (default options), and then BUILDing for polygons. Weed tolerance was set to 200; z-value = 1. The proximal tolerance was set to 10 with a z-factor of 1. CREATING A GRID Using ArcToolbox, the tin was converted to a grid using the "Import tin to grid" tool. Cell size was set to 50 (feet). Using ArcView, Analysis Properties/ Analysis Extent was set to the original point coverage with a cell size set as "current value." Map calcultor was employed to multiply the existing grid by 1. This removed some of the edges from the grid, which were of questionable accuracy because of the way that TIN handles edges. The new map calculation was saved (convert to grid).

Source_Used_Citation_Abbreviation: NGDC

Process_Date: 20010410

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NOAA Coastal Services Center

Contact_Position:

Landscape Characterization and Restoration Program (LCR) Program Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: USA

Contact_Voice_Telephone: 843-740-1200

Contact_Facsimile_Telephone: 843-740-1224

Contact_Electronic_Mail_Address: csc@csc.noaa.gov

Hours_of_Service: Monday-Friday, 8am-5pm, Eastern Standard Time

Process_Step:

Process_Description:

The grid data were converted to contours using the "Contour Wizard" within Arc Toolbox. The interval was established as 1 meter; base contour = 0; weed tolerance = 5; z-factor = 1. Within ArcView, contours less than or equal to 5 meters were selected, as were contours at 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, and 65 meters. These selected arcs were converted to a shapefile, and then suspect arcs at the edges were deleted. Artifact attributes of the conversion process also were deleted, leaving only a unique identifier and depth attribute.

Source_Used_Citation_Abbreviation: NGDC

Process_Date: 20010321

Source_Produced_Citation_Abbreviation:

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NOAA Coastal Services Center

Contact_Position:

Landscape Characterization and Restoration Program (LCR) Program Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: USA

Contact_Voice_Telephone: 843-740-1200

Contact_Facsimile_Telephone: 843-740-1224

Contact_Electronic_Mail_Address: csc@csc.noaa.gov

Hours_of_Service: Monday-Friday, 8am-5pm, Eastern Standard Time

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Complete Chain

Point_and_Vector_Object_Count: 11073

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: State Plane Coordinate System 1983

State_Plane_Coordinate_System:

SPCS_Zone_Identifier: Rhode Island

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.999994

Longitude_of_Central_Meridian: -71.500000

Latitude_of_Projection_Origin: 41.083333

False_Easting: 328083.333300

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: Coordinate pair

Coordinate_Representation:

Abscissa_Resolution:

Ordinate_Resolution:

Planar_Distance_Units: Feet

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 20925604.4720406

Denominator_of_Flattening_Ratio: 298.26

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: contour.dbf

Entity_Type_Definition: Shapefile Attribute Table

Entity_Type_Definition_Source: None

Attribute:

Attribute_Label: Contour_id

Attribute_Definition: Unique identifier for each line segment

Attribute_Definition_Source: software generated

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0

Range_Domain_Maximum: 21260

Attribute:

Attribute_Label: Depth_m

Attribute_Definition:

Depth of contour in meters. Negative values represent height above water, but are likely errors in soundings. These lines were left in the data to represent shallow waters but should not be considered entirely accurate representations of bathymetry.

Attribute_Definition_Source: from GEODAS

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -2

Range_Domain_Maximum: 65

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NOAA Coastal Services Center

Contact_Position: Clearinghouse Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: USA

Contact_Voice_Telephone: 843-740-1210

Contact_Facsimile_Telephone: 843-740-1224

Contact_Electronic_Mail_Address: csc@csc.noaa.gov

Hours_of_Service: Monday-Friday, 8am-5pm, Eastern Standard Time

Resource_Description:

Distribution_Liability:

While every effort has been made to ensure that these data are accurate and reliable within limits of the state of the art, NOAA will not assume any liability for damages caused by inappropriate use of these data.

Metadata_Reference_Information:

Metadata_Date: 20010718

Metadata_Review_Date: 20010731

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NOAA Coastal Services Center

Contact_Position: Metadata Specialist

Contact_Address:

Address_Type: Mailing and physical address

Address: 2234 South Hobson Avenue

City: Charleston

State_or_Province: South Carolina

Postal_Code: 29405

Country: USA

Contact_Voice_Telephone: 843-740-1200

Contact_Facsimile_Telephone: 843-740-1224

Contact_Electronic_Mail_Address: csc@csc.noaa.gov

Hours_of_Service: Monday-Friday, 8am-5pm, Eastern Standard Time

Metadata_Standard_Name: FGDC CSDGM

Metadata_Standard_Version: FGDC-STD-001-1998