I have an engineering document from 1991 with coordinates for a region in San Diego, CA. I can't figure which coordinate system is being used here. I would expect "NAD83 StatePlane VI ft" (2230), but the values from the doc are not within range. I've gone through known systems in the region, but still no luck.

Here is an example of three points from the document that I placed manually. Labeled are the estimated coordinates for StatePlane, and then the actual coordinates from the engineering doc. enter image description here

1 Answer 1


It looks like the engineering document points are in EPSG:26746 California ZoneVI NAD27.

enter image description here

  • I'm interested in this, did you know a few possible CRS from the location & time-frame and then brute-force through them or is there any systematic way for this problem? Jan 4 at 3:04
  • Lucky guess. QGIS makes it easy to check projections on the fly.
    – Pointdump
    Jan 4 at 7:09
  • Thank you, this was it!
    – JoshALogs
    Jan 25 at 20:09

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