NAD83 (2011) Ellipsoid

I know I have seen Ohio CORS network somewhere but I am unable to find it right now with a quick search.

While I read it all, I’m still not certain which it is. Lol

Maybe you could ask him if all VRS networks that use RTKnet software use GRS80 as the default ellipsoid?

He obviously couldn’t answer specifically for KeyNETGPS but one of my questions was if that was typically a standard for all NAD83 providers and he said yes.



This thread is an amazing example of collaborative investigation, but it really leaves me puzzled that the service provider can’t answer that question. I’m guessing the people you signed contracts with might simply be in the business of relaying a service and don’t necessarily have the technical knowledge behind the system. That would lead me to rely on Michael’s info since it has a pretty blanketing “All services at RTKNET” mention.


That’s where it’s hard to separate the salesman from the support. We got lucky to have a conversation with an admin when we got our credentials so I jotted them down immediately. :slightly_smiling_face:


Hi all,

NAD83 (2011) datum is based on GRS80 ellipsoid. You actually can check it in ReachView 3: tap on the i button while choosing the coordinate system to see the parameters defining it.


NAD83-2011 is the 2011 realization (Epoch 2010.00) of the NAD83 geographic coordinate system. NAD83 is defined on the GRS80 ellipsoid and tied to the North American tectonic plate (hence, the periodic updates). WGS84 is a geographic coordinate system defined on the WGS84 ellipsoid (also updated periodically). That said, the GRS80 ellipsoid and the WGS84 ellipsoid are very similar in size and shape.

(WGS84) UTM Zone 10N is an exampled of a projected coordinate system; where WGS84 coordinates in Zone 10N are projected (using the transverse Mercator method) onto the Zone 10N grid.

(NAD83-2011) State Plane Texas Central is another example of a projected coordinate system; the NAD83-2011 coordinates in central Texas are projected (using the Lambert Conformal Conic method) onto the Texas Central grid.


Thanks for that. It’s always great to hear multiple descriptions from different perspectives. I always see something a little clearer each time. We work in TX-C and TX-SC. Are you near down there?

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