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Which NAD 83 projection files are appropria...   Corey Staver Mar 08, 2010
Re: Which NAD 83 projection files are appro...   Melita Kennedy Mar 08, 2010
Re: Which NAD 83 projection files are appro...   Corey Staver Mar 09, 2010
Re: Which NAD 83 projection files are appro...   Melita Kennedy Mar 10, 2010
Re: Which NAD 83 projection files are appro...   Corey Staver Mar 10, 2010
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Subject Which NAD 83 projection files are appropriate for use with NAD 83/02 data 
Author Corey Staver 
Date Mar 08, 2010 
Message I've got a list of coordinates created by GPS of section and property corners, which I want to use as horizontal control for a project I'm working on. The coordinate data was acquired by a surveyor we are working with and is referenced to the following coordinate system: Nevada
State Plane Coordinate System, Zone West, North American Datum 1983/2002 Epoch (NAD 83'/02'). I'm trying to determine which projection files are appropriate to use with this data. This 2002 Epoch is something I haven't seen before, and I really don't know a whole lot about the different adjustments. I've talked it over with the surveyor, but he doesn't have much experience with GIS or ArcGIS specifically. So were stuck. The data was delivered to me in 3 formats: Geodetic, State Plane, and State Plane modified (Ground). I'm not concerned with the ground coordinates at this point, but I do want to start getting some use out of the other two sets of coordinates. There are several projection files available for each:

NAD

NAD 1983 (CSRS)
NAD 1983 (NSRS2007)
North American 1983 (CSRS98)
North American 1983 HARN
North American Datum 1983

State Plane

NAD 1983
NAD 1983 (Feet)
NAD 1983 HARN
NAD 1983 HARN (Feet, Intl and US)

Can anyone tell me which file to use and why? The data I'm creating is to be used by local government for mapping and analysis, nothing which demands extreme accuracy. But I do want to get points referenced as accurately as I can. Any help would really be appreciated! 
   
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Subject Re: Which NAD 83 projection files are appropriate for use with NAD 83/02 data 
Author Melita Kennedy 
Date Mar 08, 2010 
Message Hi,

Let's work our way through the list.

NAD 1983 (CSRS) / North American 1983 (CSRS98):
Canada, re-adjustment of NAD 1983

NAD 1983 (NSRS2007):
US, most recent adjustment

North American Datum 1983:
US and Canada, generally the original 1986 adjustment but is often used on more recent data

North American 1983 HARN:
US, National Geodetic Survey and states worked together to update NAD 1983 using GPS technology. The re-adjustments were done state-by-state, or sometimes groups of states. You'll see data labelled with a year later than 1983. That's the year of the re-adjustment. The original re-adjustments all had file-based tranformations republished. Some states did 2nd or 3rd re-adjustments but none of those have published transformations. So you should probably label this data NAD 1983 HARN.

The state plane zones are all based on a particular geographic coordinate system (datum). There are also meter, US survey feet, and int'l feet (only for some) versions of the zones. Nevada uses the US survey foot.

State Plane

NAD 1983 HARN (meters)
NAD 1983 HARN (Feet, Intl and US)


Melita 
  Melita Kennedy
ESRI Product Specialist 
   
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Subject Re: Which NAD 83 projection files are appropriate for use with NAD 83/02 data 
Author Corey Staver 
Date Mar 09, 2010 
Message Hi Melita,

Thanks for the reply. So you're recommending using the HARN coordinate systems to reference this data because the data is based on a readjustment of NAD 83 (1986) but the adjustment was prior to the NSRS 2007 adjustment, correct? Just want to make sure I understand.

All of my project data is currently referenced to NAD83 State Plane Nevada West (Feet). Rather than reproject all the project data, if I create a feature class from the GPS coordinate data referenced to one of the HARN projects, can I then use the NAD_1983_To_HARN_Nevada transformation to reproject the data back to NAD83?

Thanks for your help.

CS 
   
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Subject Re: Which NAD 83 projection files are appropriate for use with NAD 83/02 data 
Author Melita Kennedy 
Date Mar 10, 2010 
Message Hi,

Yes, to both questions.

Regards,
Melita 
  Melita Kennedy
ESRI Product Specialist 
   
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Subject Re: Which NAD 83 projection files are appropriate for use with NAD 83/02 data 
Author Corey Staver 
Date Mar 10, 2010 
Message Great, thanks for all the help!

CS