EPSG::7415 (RDnew+NAP coordinates)

[grandmaster789]

Hi there,

I've been trying to get EPSG::7415 working, but I get an error saying that the vertical datum is unavailable.

After some digging, I found that the appropriate geoid model for NAP is NLGEO2018, which is available at https://cdn.proj.org/nl_nsgi_nlgeo2018.tif. I've also tried to import that model, but there I got an error saying that this geoid is not compatible with the selected geographic coordinate system.

Do you have any suggestions?

[Paulo]

Hello Grandmaster789,

I think the NAP geoid is based on ETRS89 datum, which is different from the local/regional datum used in EPSG::7415 (Amersfoort). So to transform the NLGEO2018 file from original datum to Amersfoort datum, you can follow instructions in following tutorial https://agisoft.freshdesk.com/support/solutions/articles/31000161533-what-to-do-if-you-need-to-use-an-existing-geoid-on-another-datum...

Should work,
 see attachment 1 where I imported as DEM the nl_nsgi_nlgeo2018.tif file in a psx project., then used transform DEM from context menu to transform DEM using Amersfoort datum and correct toWGS84 parameters...
in 2nd attachement i have 2 dems (original is geoid referred to ETRS89 and 2nd to Amersfoort datum). You can then just export it as tiff referred to Amersfoort datum (again with correct toWGS84 parameters)...
in 3rd attachment I compare geographic coordinates (Amersfoort) with projected coordinates (Amersfoot / RD new + NAP Height)  of origin point  (Onze-Lieve-Vrouwentoren: 155000 mE, 463000 mN). As you can see geoid height relative to Amersfoort is -0.07 m...

[grandmaster789]

I managed to make it work, thanks for the help!

[Alexey Pasumansky]

More convenient and accurate support for Amersfoort/ND New + NAP height compound coordinate system will be added in 2.2.1 version update.