@rj-schneider?ÿ I thought I had responded earlier but donƒ??t see it. If I understand your question, you want to view geoid data files. Your message...

Why not try eBay? ?ÿScreen capture of top of results just a moment agoƒ??

This site might also be of interest:

?ÿ I vaguely remember an issue with SD card formatting. The manual linked above does reference problems with removing card during download process. ...

@gary_g?ÿ I like this one. It is also from XKCD.

As we all know, declination changes over time. The link above provides historic declination data. Page indicates accuracy is 30 minutes. Sample output...

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@mzamarrip?ÿ buena suerte en tus esfuerzos.

Also (tambien): ?ÿ ?ÿ

resources:

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@loyal?ÿ I agree. It is challenging to address the OPs question w/o more info. While the possibility of a difference in EGMs is indicated by the UNA...

@loyal?ÿ Good article. I also recommend a 2018 FIG paper ƒ??Towards ?ÿThe Modernization of Indian Vertical Datumƒ? by Dr S K Singh. The 1909 IVD wa...

FWIW, Using coordinates for an IGS site in Bengaluru, India I ran the UNAVCO GEOID HEIGHT tool/p> I specified the EGM2008 and the EGM96 models. The ...

@rj-schneider?ÿ from todayƒ??s Guardianƒ??