Global Mapper v25.0

OSGB OSTN15 supported?

veddycent
veddycent Global Mapper User
Hi all,

I'm currently using v20.1 and wondering whether GM is using OSTN02 or OSTN15 for OSGB36 transforms?

I came across the same question on here from 2018 but doesnt have a response so I'm asking again.

Any help would be much appreciated.
Regards
V
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Answers

  • veddycent
    veddycent Global Mapper User
    To add to the above. I imported a KMZ which has been exported from Arc using NTv2 OSTN02 and loaded into GM with the original SHP and a KMZ exported from GM.

    The SHP and KMZ from GM matched perfectly but the KMZ from ArcGis did not. I assume its because Arc is using a newer projection than GM.

    Is there any way to add the newer projection to GM?

    Any help would be much appreciated.
    Regards
    V
  • I do support the request of @veddycent to embed the NTv2 OSTN15 transformation in GM (this is widely used nowadays).

    OSTN15 transformation (OSGB36 to ETRS89 NTv2 version) has EPSG code 7709, Ordance Survey has published a toolpack for developers on their site:
    https://www.ordnancesurvey.co.uk/business-government/tools-support/os-net/for-developers)
  • bmg_bob
    bmg_bob Global Mapper Programmer
    Hello,

    We have an open feature request (GM-6663) to add support for the OSTN15 transformation. I have added your information to the feature request and bumped up the number of users requesting this. Thank you.

    Cheers,
    Bob
  • Much appreciated, thanks!
  • Please add myself to the OSTN15 user request list!
  • bmg_bob
    bmg_bob Global Mapper Programmer
    Answer ✓
    Hello,

    Support for OSTN15 was added in Global Mapper 22.1, which is available now.

    Cheers,
    Bob
  • When I re-project from WGS84 to OSTN15 using either the OS GridInquest II software, or my Trimble software, I get a result thats within 2mm of each other. When I try this with the Global Mapper demo my result is more than a metre out.