Global Mapper v25.0

how to add a new GSB file

To obtain a new datum in the list of datums
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Answers

  • bmg_bob
    bmg_bob Global Mapper Programmer
    Hello,

    Can you please provide more details about what you are trying to do?  I am not familiar with a GSB file.

    Cheers,

    Bob
  • Mykle
    Mykle Global Mapper User Trusted User
    Bob,
    "Golden Software Boundary [.GSB] files contain geographic data in a binary format.
    In Surfer, this format includes polylines, polygons, and points."

    We use Surfer here, and I see their sample files for Calif. and Colo.
    Otherwise there are numerous GSB2 files in Global Mapper that appear to be a different binary format.
    Mykle
  • JeffH@BMG
    JeffH@BMG Global Mapper Developer Trusted User
    .GSB files might also refer to "Grid Shift Binary" files. This link seems to have some information about this file format: https://github.com/Esri/ntv2-file-routines/blob/master/README.md

    Quotes:

    "The NTv2 (National Transformation Version 2) file standard was developed by the Canadian government in 1995 to describe shift data for transformations of geographic points from one datum to another (originally from NAD27 to NAD83). This file format has since then come into world-wide use, with over a dozen countries publishing NTv2 files for their areas. Unfortunately, there is a dearth of documentation on the contents and syntax of NTv2 files, and there are no easily available programs for creating and/or dumping them. This distribution is intended to address this need."

    "All binary NTv2 files have the extension ".gsb", for "Grid Shift Binary". Correspondingly, for the ascii versions of the file, we propose the extension ".gsa", for "Grid Shift Ascii". We will refer to these files as GSB and GSA files. The sample programs included here automatically determine whether a NTv2 file is binary or ascii by inspecting the extension of the file name (not the contents of the file)."

    Due to the references to datum in this description, that may be more relevant to egsankara's query.

    ~Jeff