Citation:
Citation_Information:
Originator: U.S. Geological Survey
Originator: Coastal and Marine Geology Program
Publication_Date: 2013
Title:
j695mb.m77t and j695mb.h77t: MGD77T data and header files for single-beam bathymetry data for field activity J-6-95-MB in Monterey Bay from 10/16/1995 to 11/30/1995
Geospatial_Data_Presentation_Form: tab-delimited ASCII text files
Publication_Information:
Publication_Place: St. Petersburg, FL
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/ds/757/data/m77t/j695mb.m77t
Larger_Work_Citation:
Citation_Information:
Originator: Heather A. Schreppel
Originator: Carolyn H. Degnan
Originator: Dan R. Metzger
Originator: Shawn V. Dadisman
Publication_Date: 2013
Title:
Archive of U.S. Geological Survey Single-beam Bathymetry, 1969-2000
Edition: 1.0
Geospatial_Data_Presentation_Form: Digital Document
Series_Information:
Series_Name: U.S. Geological Survey Data Series
Issue_Identification: 757
Publication_Information:
Publication_Place: St. Petersburg, FL
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/ds/757
Description:
Abstract:
Single-beam bathymetry data along with DGPS navigation data was collected as part of the U.S. Geological Survey cruise J-6-95-MB. The cruise was conducted from in Monterey Bay, California from October 16 to November 30, 1995. The chief scientists were Roberto Anima, Andy Stevenson, and Steve Eittreim all from the USGS Coastal and Marine Geology office in Menlo Park, CA.
The purpose of this cruise was to produce a mosaic of the northern Monterey Bay Santuary continental shelf area from as near shore out to the continental slope, and to collect digital subbottom profile data to better understand the shallow tectonics and paleomorphology of the sanctuary. The geophysical source was a Lowrance fathometer.
These data are reformatted from space-delimited ASCII text files located in the Coastal and Marine Geology Program (CMGP) InfoBank field activity catalog at
http://walrus.wr.usgs.gov/infobank/j/j695mb/html/j-6-95-mb.meta.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.
These data and information are intended for science researchers,students, policy makers, and general public. These data are not to be used for navigation purposes. The data are reformatted into MGD77T standard format for inclusion into NOAA's NGDC geophysical database. From there the data will be made available to GeoMapApp (
http://www.geomapapp.org/) and Virtual Ocean (
http://www.virtualocean.org/) Earth-browsing software. Access to the data is also provided via the USGS Coastal and Marine Geoscience Data System (
http://cmgds.marine.usgs.gov/).
The navigation data are digitally collected using a Differential Global Positioning System (DGPS). The DGPS is a space-based satellite navigation system maintained by the United States government and is accessible using a GPS receiver. Data accuracy is based on individual receiver models, and most GPS data is collected in the WGS84 horizontal datum.
The Data Acquisition, Processing, and Storage (DAPS) group performs a number of processing steps to the navigation data once it is collected which can vary by cruise. These steps are outlined within the header information in each individual digital navigation (.0xx, .6xx) space-delimited ASCII data file. The header information rows are indicated by lines beginning with the character "!". The single-beam bathymetry data are collected both digitally and as analog records with a Lowrance fathometer. The bathymetry datasets were commonly processed using three programs: (A) Batred, which calculates depth from travel times; (B) nosamebathy, which eliminates identical adjacent bathymetry values; and (C) nozerobathy, which removes records with a depth value of "0.0". However, not all of the datasets included in this report were processed with one or more of these programs. If the data was not run through these programs it was reformatted using the most recent "best file" on InfoBank, often these were categorized by InfoBank as raw bathymetry files. Details about which processing steps were taken by the DAPS group can be found in the header information of the bathymetry and navigation ASCII files downloaded from InfoBank.
Prior to reformatting the data into MGD77T format the "best" bathymetry and navigation files from InfoBank were edited to remove the header information and reformatted using Excel 2010 to separate the data into columns based on tabs. Next the bathymetry and navigation files were merged based on time and latitude and longitude. The combined navigation and bathymetry was saved as a .txt file. This combined bathymetry and navigation file was used as an input file into the GEODAS ReFormat to MDG77T program developed by NOAA's NGDC. The program outputs the reformatted data as a tab-delimited .m77t file. The program is available for use at:
http://www.ngdc.noaa.gov/mgg/gdas/gx_announce.Html. For information regarding fields found within the MGD77T files, please refer to the publication, Hittelman and others (2010), found within the Cross-reference section of this metadata file.
Each MGD77T data file also has an accompanying header file (.h77t). The fields within these header files are also defined in the aforementioned publication. Fields are populated based on InfoBank metadata records, digital data file headers, and accompanying publications (often cruise reports) for the survey. If a field is unknown or did not apply to the dataset it is intentionally left blank.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19951016
Ending_Date: 19951130
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -122.38052
East_Bounding_Coordinate: -121.89430
North_Bounding_Coordinate: 37.09805
South_Bounding_Coordinate: 36.80412
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:8f519481-8214-4c15-b309-8b1e9cab4797
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: geoscientificinformation
Theme_Keyword: oceans
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Marine Geology
Theme_Keyword: Marine Geophysics
Theme_Keyword: Single-beam Bathymetry
Theme_Keyword: Water Depth
Theme_Keyword: Seafloor Topography
Theme_Keyword: Marine Seismic
Theme:
Theme_Keyword_Thesaurus: Data Categories for Marine Planning
Theme_Keyword: distributions
Theme_Keyword: bathymetry and elevation
Theme:
Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords
Theme_Keyword: single-beam echo sounder
Theme_Keyword: marine geophysics
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: single-beam echo sounder
Theme_Keyword: bathymetry measurement
Theme_Keyword: bathymetry
Theme_Keyword: marine geophysics
Place:
Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: State of California
Place_Keyword: North Pacific Ocean
Place_Keyword: Northern California
Place_Keyword: Monterey Bay
Access_Constraints: None. These data are held in the public domain.
Use_Constraints:
This information is not intended for navigational purposes.
Read and fully comprehend the metadata prior to data use. Uses of these
data should not violate the spatial resolution of the data. Where
these data are used in combination with other data of different resolution,
the resolution of the combined output will be limited by the lowest
resolution of all the data.
Acknowledge the U.S. Geological Survey in products derived from these data.
Share data products developed using these data with the U.S. Geological
Survey.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Heather A. Schreppel
Contact_Organization:
Cherokee Nation Technology Solutions, contracted to U.S. Geological Survey
Contact_Position: IT Management Specialist/Database Support Assistant
Contact_Address:
Address_Type: mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: (727) 803-8747, ext. 3013
Contact_Electronic_Mail_Address: hschreppel@usgs.gov
Data_Set_Credit:
Roberto Anima (Chief Scientist, USGS Western Region);
Andy Stevenson (Chief Scientist, USGS Western Region);
Steve Eittreim (Chief Scientist, USGS Western Region)
Cross_Reference:
Citation_Information:
Originator:
Hittelman, Allen M., Groman, Robert C., Haworth, Richard T., Holcombe, Troy L., McHendrie, Graig, Smith, Stuart M., and Metzger, Dan R.
Publication_Date: 2010
Title: The marine geophysical data exchange format - MGD77 / MGD77T
Publication_Information:
Publication_Place: Boulder, CO
Publisher:
National Geophysical Data Center, National Oceanic and Atmospheric Administration
Other_Citation_Details: 25 p.
Online_Linkage: http://www.ngdc.noaa.gov/mgg/dat/geodas/docs/mgd77.pdf
