Am I using vanilla NAD 1983

[AngelaGruber]

Hello everyone,

I have a question about NAD 83.  I am not very knowledgeable about the
different versions of NAD 83, but I am hoping someone can help.  My organization uses GIS data in State Plane,
specifically this:  NAD_1983_StatePlane_Texas_South_Central_FIPS_4204_Feet.  When I look at the Coordinate System list under Data Frame Properties in ArcMap, I see a lot of choices, such as:  NAD 1983 (2011) (US Feet), NAD 1983 (CORS96) (US Feet), NAD 1983 HARN (US Feet), and NAD 1983 (US Feet).  We use the last one.

Is it correct to assume that NAD 1983 (US Feet) is the original version of NAD 1983 (1986)?

I read another discussion that touched on this topic, but it
was really more complicated, involving transformations with 7 parameters,
etc.  It was a bit over my head.  I just want to know if I am working in vanilla NAD or something else.

I have attached a screen shot of the Coordinate System list.

Thanks for your help,

Bea

[AngelaGruber]

Margaret...

Thank you so much for this information.  I understand what you are saying about the semi-major and semi-minor axes.  I needed that explanation.  So to clarify things for myself: when I have GIS data in vanilla NAD 83 and GPS data that has been post-processed against a WGS 84 (ITRF00) base station, I should use the WGS_1984_(ITRF00)_To_NAD_1983 transformation.  Have I got it right?

I certainly do appreciate your help,

Angela

[MargaretMaher]

Good morning, Angela!  You are absolutely correct.  You will use the transformation WGS_1984_(ITRF00)_To_NAD_1983 (WKID 108190), as this is the most accurate transformation available at this time.   Have a great day! Margaret

[AngelaGruber]

Thank you again, Margaret!

This was very helpful.