I didn't get my act together to get a longer topic into the help for ArcGIS Desktop/Server 10.5 or ArcGIS Pro 1.4. I was specifically tasked with writing a white paper/blog posts/etc. about it. Maybe this week, while it's quiet!
Particularly for ArcGIS Pro, we're trying to keep the core setup as small as possible. Adding even the 2.5'x2.5' EGM2008 and the GEOCON files is close to 0.5 GB. Management said NO. We had discussed making a separate data install years ago, when the ArcGIS Desktop install was creeping towards requiring either another CD or maybe a DVD, but managed to scrape through.
So with geoid models coming from several countries, and more grid-file-based transformations all the time, it was decided that we've start a separate setup for that data. It also allows customers to decide to not install everything if they want. At some point, we'll likely move the existing NADCON/HARN/NTv2 files from the core setups into this separate setup, but there's no timeline for that yet.
There are two versions of the data setups. One is 32-bit and used for Desktop, Server, Engine, etc. The other is 64-bit and currently used only for ArcGIS Pro. The separation has mostly to do with being able to access the 32-bit and 64-bit registries, but ArcGIS Pro is also the one most likely to get out-of-sync with the others when dealing with release schedules.
The GEOCON files are for the US and convert between the latest NAD 1983 HARN, NAD83 (NSRS2007), and NAD83 (2011). These files are from the GEOCON and GEOCON11 1.0 versions. There's a new version in beta from the NGS, that includes multiple HARN realizations (the last one is now called an FBN). While it's in beta, we haven't added support for them yet. The transformations that use these files are:
NAD_1983_HARN_To_NSRS2007_GEOCON_CONUS
NAD_1983_HARN_To_NSRS2007_GEOCON_Alaska
NAD_1983_HARN_To_NSRS2007_GEOCON_Puerto_Rico_Virgin_Islands
NAD_1983_NSRS2007_To_2011_GEOCON11_CONUS
NAD_1983_NSRS2007_To_2011_GEOCON11_Alaska
NAD_1983_NSRS2007_To_2011_GEOCON11_Puerto_Rico_Virgin_Islands
The Vertical folder contains the EGM84 and EGM2008 2.5'x2.5' files. The EGM96 file is already in the core software. The EGM2008 1'x1' has a separate entry in the setup because it's so large. We aren't using it by default because of that.
WGS_1984_To_WGS_1984_EGM2008_1x1_Height
WGS_1984_To_WGS_1984_EGM2008_2.5x2.5_Height
WGS_1984_To_EGM_1996_Geoid_1
WGS_1984_To_EGM_1996_Geoid_2 (interpolation is natural spline)
WGS_1984_To_EGM_1984_Geoid_1
WGS_1984_To_EGM_1984_Geoid_2 (interpolation is natural spline)
The Vertical folder also contains the US Geoid12b files (Alaska, Guam and Northern Marianas, Hawaii, Puerto Rico and US Virgin Islands, American Samoa, and CONUS) and the VERTCON files. We have the east, central, and west files, plus a combined one that we built in-house.
NAD_1983_2011_To_NAVD88_CONUS_GEOID12B_Height
NAD_1983_2011_To_NAVD88_Alaska_GEOID12B_Height
NAD_1983_PA11_To_NAVD88_Hawaii_GEOID12B_Height
NAD_1983_2011_To_PRVD02_GEOID12B_Height (Puerto Rico)
NAD_1983_PA11_To_ASVD02_GEOID12B_Height (American Samoa)
NAD_1983_MA11_To_GUVD04_GEOID12B_Height (Guam)
NAD_1983_2011_To_VIVD09_GEOID12B_Height (US Virgin Islands)
NAD_1983_MA11_To_NMVD03_GEOID12B_Height (Northern Marianas)
NAD_1983_To_NAVD88_CONUS_GEOID12B_Height
NAD_1983_To_NAVD88_Alaska_GEOID12B_Height
NAD_1983_To_NAVD88_Hawaii_GEOID12B_Height
NAD_1983_To_PRVD02_GEOID12B_Height (Puerto Rico)
NAD_1983_To_VIVD09_GEOID12B_Height (US Virgin Islands)
NGVD29_To_NAVD88_NAD27_3_East
NGVD29_To_NAVD88_NAD27_2_Central
NGVD29_To_NAVD88_NAD27_1_West
NGVD29_To_NAVD88_NAD27_ECW (conus grid)
NGVD29_To_NAVD88_NAD83_East
NGVD29_To_NAVD88_NAD83_Central
NGVD29_To_NAVD88_NAD83_West
NGVD29_To_NAVD88_NAD83_ECW (conus grid)
NGVD29_To_NAVD88_HARN_East
NGVD29_To_NAVD88_HARN_Central
NGVD29_To_NAVD88_HARN_West
NGVD29_To_NAVD88_HARN_ECW (conus grid)
Note: The NAD27/NAD83/HARN in the transformation name indicates the GeoCRS used to interpolate the offset values from the grid files. The VERTCON files are imprecise enough that it doesn't matter which NAD83 adjustment you use for the interpolation. However, we still need to them listed separately. We may end up adding NSRS2007 and 2011 variants in a future release.
We had a few new NTv2 grids that ended up in the new setup as well. I suggested putting them in the core software with the existing ones, but no go. For Switzerland, we added a replacement for an existing grid, CHENYX06_etrs.gsb. For the UK, we added OSTN15_NTv2.gsb and osgb36_xrail84.gsb. The latter is for the CrossRail project in the greater London area. The transformations that use these files are below:
CH1903_To_CHTRF95_1_NTv2
CH1903_To_ETRS_1989_2_NTv2
CH1903_To_WGS_1984_3_NTv2
ETRS_1989_To_OSGB_1936_OSTN15
WGS_1984_To_OSGB_1936_OSTN15
OSGB_1936_To_Xrail84_NTv2
I'm working on other countries' geoid files but redistribution rights are often an issue.
Melita
***Edited to list the transformations that use these files.
