RIGIS uses the Rhode Island State Plane U.S. Survey Foot NAD 83 coordinate system (EPSG 3438) to share practically all of the data that have been contributed to the consortium. This coordinate system is listed as “NAD_1983_StatePlane_Rhode_Island_FIPS_3800_Feet” within Esri ArcGIS software.
Because we frequently use ArcGIS software to help us compile metadata, you’ll occasionally see the Esri variant of this coordinate system listed in our documentation instead, EPSG 102730. These two variants are essentially the same as far as RIGIS data distribution are concerned.
Some datums – in this case, NAD 1983 – have different versions (a.k.a. realizations, refinements, or epochs). The NAD 83 epoch used by RIGIS is 1986.
Esri uses slightly different datum titles than those used by other organizations such as the National Geodetic Survey, making it challenging at times to find more detail about which datum epoch is being applied. Below is a table that lists some of the title differences that are most relevant to us here in Rhode Island. (I left CSRS in the list because that was always a bit of a mystery for me.)
|National Geodetic Survey||Esri|
|NAD 83 (1986)||NAD 83|
|NAD 83 (1992)||NAD 83 (HARN)|
|NAD 83 (1996)||NAD 83 (CORS96)|
|NAD 83 (2007)||NAD 83 (NSRS2007)|
|NAD 83 (2011)||NAD 83 (2011)|
|Canadian Spatial Reference System||NAD 83 (CSRS)|
Special thanks to Daniel Martin, the Northeast Regional Geodetic Advisor, for providing the above list! Contact information for Dan and the rest of the geodetic advisor team is available at https://www.ngs.noaa.gov/ADVISORS.