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    • Calibration Base Lines for Electronic Distance Measuring Instruments (EDMI)

    Metadata Updated: July 31, 2025

    A calibration base line (CBL) is a precisely measured, straight-line course of approximately 1,400 m used to calibrate Electronic Distance Measuring Instruments (EDMI). A CBL usually consists of four segments ranging from 150 to 1,400 m whose lengths are measured with two high precision EDMI. Since the program began in 1974, NGS has established more than 300 base lines throughout the United States in cooperation with government agencies, universities and professional groups. Participating organizations must select a suitable site that is accessible for public use and install the base line markers 2 to 3 months before measurements are taken. Published CBL distances are available from the National Geodetic Survey, 301-713-3242 or ngs.infocenter@noaa.gov. For more information, please refer to: [1] NOAA Technical Memorandum NOS NGS-8 - Establishment of Calibration Base Lines (1994). [2] NOAA Technical Memorandum NOS NGS-10 - Use of Calibration Base Lines (1977). Both publications are available in pdf from http://www.ngs.noaa.gov/PUBS_LIB/pub_index.html.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Date July 24, 2025
    Metadata Created Date October 31, 2024
    Metadata Updated Date July 31, 2025
    Reference Date(s) 1974 (creation), 1974 (publication)
    Frequency Of Update asNeeded

    Metadata Source

    Harvested from NOS NGS

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Date July 24, 2025
    Metadata Created Date October 31, 2024
    Metadata Updated Date July 31, 2025
    Reference Date(s) 1974 (creation), 1974 (publication)
    Responsible Party NGS Communications and Outreach Branch (Point of Contact, Custodian)
    Contact Email
    Guid gov.noaa.nmfs.inport:39910
    Access Constraints Cite As: National Geodetic Survey, [Date of Access]: Calibration Base Lines for Electronic Distance Measuring Instruments (EDMI) [Data Date Range], https://www.fisheries.noaa.gov/inport/item/39910., Access Constraints: None, Use Constraints: None, Distribution Liability: none
    Bbox East Long -67
    Bbox North Lat 71
    Bbox South Lat 18
    Bbox West Long -175
    Coupled Resource
    Frequency Of Update asNeeded
    Harvest Object Id c5f0acdb-5ace-4378-a9de-fca5111fbac9
    Harvest Source Id ea6e63e6-96bb-4fb1-a72f-b7af08062c83
    Harvest Source Title NOS NGS
    Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
    Lineage
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-175.0, 18.0], [-67.0, 18.0], [-67.0, 71.0], [-175.0, 71.0], [-175.0, 18.0]]]}
    Progress onGoing
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 1974

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