I was thinking that, but figured you did that for a specific reason. Normally we separate the horizontal from the vertical because in our scenario the vertical is usually local.
Odd thing is that the other two golf courses that I did the same for, they worked perfectly fine. So is it a rule of thumb that I should not use NAVD for anything when collecting GCPs in a state plane?
I wouldn’t. Your GCP’s should be defined by what you shoot, hopefully from a known point. In our scenario it is a localized ground-leveled benchmark.
Makes sense. Still learning every day. Thanks to everyone for all the help and guidance.
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Trying to understand this better. I’m running an RS2 via NTRIP. When I shoot without NAVD, it is getting the exact location vs Elippsoid/Orthometric?
Sorry, I don’t use NTRIP so you may be right and have to do that for compatibility with the corrections provider. RV3 now has GEOIDs, but no orthometric. How are you finding orthometric heights relative to ground-leveled survey/engineering/construction vertical benchmarks?
I thought geoids were orthometric?
Maybe you are thinking geodetic? The orthometric height is the distance from the geoid to the surface, but it is a mathematical number and since we cannot see and measure from the geoid we do land level loops from benchmarks.
Hi there,
I’ve done some research, and there seems to be no generally accepted terminology in the industry 
Making it easier, we have three surfaces: ellipsoid, geoid, and topography (our real terrain). Therefore, there are three values:
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From ellipsoid to topography. This is the ellipsoidal height, no doubts
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From geoid to topography. It’s called orthometric height
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From ellipsoid to geoid
The last one is the most complicated. In some sources, it’s called Geoid-ellipsoid separation. And the geoid height term is taken to be synonymous with orthometric height.
From another point of view, geoid height is the height from ellipsoid to geoid. And orthometric is just orthometric, without any other options.
I prefer the second option. Just because it causes less confusion. However, we need to keep in mind that there are different opinions, and we may “speak a different languages” sometimes.
Regarding your first question:
NAD83 is a horizontal datum based on the GRS1980 spheroid. So, when we say “NAD83 ellipsoidal heights”, we mean height above GRS1980.
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What about the Telluroid! 
Hi James,
To be honest, I haven’t heard about using heights above the Telluroid exactly. However, there is a quasi-geoid which is a surface parallel to the Telluroid transferred to the mean sea level. And heights above quasi-geoids are called normal heights. Have you ever heard some other terminology? 
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Hi Svetlana,
Thanks for the reply 
Your posts are very useful.
The quasi-geoid is relevant to us in Australia as AUSGeoid09 and Ausgeoid2020 are quasi-geoid models. As you mentioned, this means they compute height along a normal ie. NOT orthometric heights.
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