NTV2 Grid PD 83 ->ETRS 89 for Thuringia

[bstroebl]

Information page: https://sapos.thueringen.de/ThuT_dll.php (in German)
download link: https://sapos.thueringen.de/DOWNLOAD/ntv2gridth.ZIP

[bstroebl]

I asked the provider to add licensing information to this ticket.

[bstroebl]

The grid is open data, licensed under Data licence Germany – attribution – version 2.0
The name of the provider as in (2) 1. of the license is © GDI-Th

[kbevers]

The grid is open data, licensed under Data licence Germany – attribution – version 2.0

Is this info publicly available somewhere?

[bstroebl]

This info results from personal communication, stating that the NTV2 grid is in no way different than any other open data published by the same authority https://www.geoportal-th.de/de-de/Downloadbereiche/Download-Offene-Geodaten-Th%C3%BCringen (in German)
edit: typo

[kbevers]

Okay, I guess that'll do although it would be preferable to have them mention it explicitly in relation to the grid files. Thanks for looking in to this.

[rouault]

@bstroebl Could the provider consider registering their grid to EPSG as I don't see it registered yet ? Quoting CONTRIBUTION.md "If the gris is not yet registered in the EPSG database, you are strongly encouraged to engage with EPSG to register it. This will make its addition to PROJ and its later maintainance much easier. http://www.epsg.org/EPSGDataset/Makechangerequest.aspx explains the procedure to follow to submit a change request to EPSG."

[rouault]

Another thing to check with the provider is the units of the accuracy values in the NTv2 file (since they provide non-zero values). As you can see in https://github.com/OSGeo/PROJ/wiki/Units-of-NTv2-accuracy-samples-%3F , producers have more or less randomly selected arc-seconds or metre and it is impossible to be sure without the confirmation from the provider. (for clarity, I speak only about the accuracy values, not the offset values themselves which are all in arc-second)

[rouault]

WARNING: This repository is no longer open for adding new datasets. Starting with PROJ 7, the PROJ-data repository is the new home for PROJ datasets.

Go to its CONTRIBUTING instructions