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When working with data from different sources, they often come in with different EPSG codes, even when they are using the same nominal projection. For example, I often work in Washington State Plane North NAD83 in US feet. Using QGIS I generally select EPSG 2285, but when I'm working with a shapefile generated in ArcMap, it often comes in on EPSG 102748. I recently opened a geodatabase also in Washington State Plane North NAD83 in US Feet that was in EPSG 6597. A search on EPSG.io also lists EPSG 32148 as a Washington State Plane North NAD83 in US Feet.

When using QGIS all of these appear to perform the same, and I haven't run into issues with with strange results because of different projections. None of these projections appear to be deprecated, and I haven't found anything to recommend one vs another. Is there any reason to prefer or avoid any of these, or am I getting concerned over trivia?

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  • EPSG official numbers are between 1024 to 32766, anything else you see is probably an ESRI code rebadged.
    – Ian Turton ♦
    May 14, 2019 at 17:16
  • Have you checked, which projection is the most recent?
    – Erik
    May 14, 2019 at 17:19
  • Note: We changed the WKID of 102748 in version 9.0 to 2285, but sometimes it used over the "latest" WKID so that the definition will be understood by servers using older versions. We're starting to do multiple checks--does server understand latest? Use that. If not, try old WKID. - I'm an Esri employee.
    – mkennedy
    May 14, 2019 at 19:44

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See the epsg geodetic registry for details about the different variants of Washington North (ftUS) https://www.epsg-registry.org/

The difference between the NAD83 variants is only noticable when you are aiming for high accuracy.

US foot

- NAD83(2011) / Washington North (ftUS)     EPSG::6597 
- NAD83(HARN) / Washington North (ftUS)     EPSG::2926  
- NAD83(NSRS2007) / Washington North (ftUS)     EPSG::3690  
- NAD83 / Washington North (ftUS)     EPSG::2285 
- NAD 1983 StatePlane Washington North FIPS 4601 Feet     ESRI::102748 (not EPSG!)

Meters:

- NAD83 / Washington North     EPSG::32148
- NAD83(2011) / Washington North     EPSG::6596
- NAD83(HARN) / Washington North      EPSG::2855 
- NAD83(NSRS2007) / Washington North     EPSG::3689  
- NAD27 / Washington North     EPSG::32048
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