Global Mapper v25.0

Edit built-in datum

Vincent
Vincent Global Mapper UserTrusted User
edited June 2008 in Technical Support
I would like to edit some of the built-in datum with my own parameters. Is it possible to do it ?
Thank you.

Comments

  • global_mapper
    global_mapper Administrator
    edited June 2008
    It is not possible to edit the built-in datums. You need to create a custom datum with the parameters that you want to use. You can do this on the Projection tab of the Configuration dialog.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Vincent
    Vincent Global Mapper User Trusted User
    edited June 2008
    Thanks.
    For the moment I create my own datum. Do you plan to edit the transformation parameters for the Tananarive 1925 datum ?
    You use the NIMA transformation parameters (Tananarive 1925 > WGS84) :
    Tx = -189 m
    Ty = -242 m
    Tz = -91 m
    Those parameters are inacurrate.
    French geographic office (IGN) proposes a better set of parameters :
    Tx = -179 m
    Ty = -229 m
    Tz = -109 m
    I recently conducted surveys in Madagascar, and I can confirm that this set of parameters is much more accurate.
    Would you mind updating this parameters in the Global Mapper built-in datum ?
    Thanks
  • global_mapper
    global_mapper Administrator
    edited June 2008
    I'll take your word for it that those parameters are more accurate (apparently EPSG has not picked up on those parameters yet). I have placed a new build at http://www.globalmapper.com/global_mapper9.zip with the updated parameters for you to try. Simply download that file and extract the contents into your existing v9.xx installation folder to give it a try.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Vincent
    Vincent Global Mapper User Trusted User
    edited June 2008
    I'm still using version 8 of Global Mapper (my office has not yet updated the software...). Can I use this new build ?
    Thanks
  • global_mapper
    global_mapper Administrator
    edited June 2008
    You would need to have a v9 license to use the new build as the update is in v9 only.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com