Fwd: Transforming Data from NAD 83 State Plane Feet to NAD 83 (2011) State Plane Feet
RIGIS Data Manager
From: Mitchell, Jared (DOT) <Jared.M...@dot.ri.gov>
Date: Wed, Nov 26, 2025 at 11:37 AM
Subject: Transforming Data from NAD 83 State Plane Feet to NAD 83 (2011) State Plane Feet
To: ri...@uri.edu <ri...@uri.edu>
Cc: Kut, Stephen (DOT) <steph...@dot.ri.gov>
Hi All (or just Aimee?),
We have been discussing projections and transformations here at RIDOT as part of our process for migrating to the cloud and setting up services for a data collection project we have ongoing and we wanted to ask what RIGIS has/had done for their own datasets.
It is possible to just reproject a data set that is in vanilla NAD 83 (RI SPF) to the latest realization (2011) and there probably wouldn’t be much noticeable difference to the geometry, but as an exercise in following best practices there is an ESRI blog that steps through the “correct” way to transform the data.
“The correct way to convert data in historic U.S. datums is to transform them through all in-between NAD83 datums, that is, from NAD27 to NAD83 (1986) to NAD83 (HARN) to NAD83 (FBN) to NAD83 (NSRS2007) and finally to NAD83 (2011). Transformations should not be performed between unrelated geographic coordinate systems, such as WGS 1984. The NADCON 5.0 transformations listed below are available in ArcGIS Pro (see How to transform data in ArcGIS Pro). The following lists give the order in which transformations should be used:
For Contiguous United States (CONUS)
NAD_1927_To_NAD_1983_7 (WKID::8555)
NAD_1983_To_NAD_1983_HARN_47 (WKID::8556)
NAD_1983_HARN_To_FBN_NADCON5_3D_CONUS_1 (WKID::8861)
NAD_1983_FBN_To_NSRS2007_NADCON5_3D_CONUS_1 (WKID::8862)
NAD_1983_NSRS2007_To_2011_NADCON5_3D_CONUS_1 (WKID::8559)”
Approximate timeline of NAD83 realizations and re-adjustments.
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We were able to set up a process for stepping through the transformations outlined in the blog using FME, but one step we are unsure of is for going between NAD 1983 HARN to NAD 1983 (FBN) and then from that to NSRS2007.
I cannot seem to find any confirmation that the FBN (Federal Base Network) has any state-specific projections or if it really is necessary for going from HARN to NSRS2007. I had previously never come across FBN before.
Just wondering if any of you at URI were aware of this process or familiar with some of these transformations.
Thanks!
Jared W. Mitchell
Office of Asset Information Systems (OAIS)
Rhode Island Department of Transportation
Two Capitol Hill, Room 330
Providence, Rhode Island, 02903