I've got a a database of feature classes that were somehow transformed into a custom projection that I don't understand, and there does not seem to be a way to get back out of. The projection data are below. Three questions:

  1. How did it get this way?
  2. How can it be made into a standard projection?
  3. Can you recover a file that was transformed out of this projection?

This is what the projection says:

Authority: Custom

Projection: Mercator_Auxiliary_Sphere
False_Easting: 0.0
False_Northing: 0.0
Central_Meridian: 0.0
Standard_Parallel_1: 60.0
Auxiliary_Sphere_Type: 0.0
Linear Unit: Foot_US (0.3048006096012192)

Geographic Coordinate System: GCS_WGS_1984
Angular Unit: Degree (0.0174532925199433)
Prime Meridian: Greenwich (0.0)
Datum: D_WGS_1984
  Spheroid: WGS_1984
    Semimajor Axis: 6378137.0
    Semiminor Axis: 6356752.314245179
    Inverse Flattening: 298.257223563

What the heck is this?

  • 2
    Please edit the question to specify in which database (with version) the feature classes are located. You've tagged both ArcGIS 10.1 and 10.2, but don't mention software in the question body -- Please clarify.
    – Vince
    Apr 22, 2016 at 14:55
  • Where did you get the file from?
    – Adam Kara
    Apr 22, 2016 at 14:56
  • It's a 10.2 file geodatabase. (the forum software would not let me post with just the 10.2 tag, so I added 10.1). It's a database one of our district offices has been using for some time. One of the feature classes was already transformed w/o backup and they can't get it back, so they sent the rest to me to fix. It makes no sense to me. Apr 22, 2016 at 15:02
  • Here's what it transformed into, it somehow mismatched the proejction and datums: PROJCS["NAD_1983_HARN_StatePlane_Ohio_South_FIPS_3402_Feet", GEOGCS["GCS_North_American_1983_HARN", DATUM["D_North_American_1983_HARN", SPHEROID["GRS_1980",6378137.0,298.257222101]], PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]], PROJECTION["Lambert_Conformal_Conic"], PARAM["False_Easting",1968500.0], PARAM["False_Northing",0.0], PARAM["Central_Meridian",-82.5], PARAM["Standard_Parallel_1",38.73333333333333], PARAM["Standard_Parallel_2",40.03333333333333], PARAM["Latitude_Of_Origin",38.0], Apr 22, 2016 at 15:06
  • Does your district office use any custom projections? I am in Northeast Ohio and I have dealt with these issues before from various sources. Cuyahoga County (where Cleveland is) used to use CRGS as a custom projection and everyone else uses State Plane North. The people before at my company sucked and made a custom projection based off CRGS and because it was made in that projection all of the geometry was unusable since I couldn't reproject it. I could never come up with a solution to fix what they did.
    – Adam Kara
    Apr 22, 2016 at 15:15

1 Answer 1


Fixed! - but this required a bit of luck. I was able to deduce what projection the shapefiles were actually in (The .prj file was incorrect). I then replaced the .prj file above with a .prj file from a correctly projected shapefile and I was able to get everything back to normal.

Thanks for the help, Adam's comment gave me a clue.

  • 2
    If the data was really in Mercator_auxiliary_sphere, you could unproject it to latitude-longitude (geographic coordinate system). Then it would either be on WGS84 or NAD83 HARN (most likely), and you could reproject it to the state plane zone definition.
    – mkennedy
    Apr 22, 2016 at 18:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.