[Proj] Local cartesian to UTM using PROJ.4

Greg Troxel gdt at ir.bbn.com
Tue May 15 14:42:52 EDT 2007

Frode Tennebø <frode at tennebo.com> writes:

> I'm trying to perform a transformation of a position in a local
> carteisan system, grid north in meters (XYZ) relative to a UTM/WGS84
> (ENA) center with the result in UTM/WGS84.  I have tried Geotrans
> (Local cartesian -> UTM, WGE/ WGS84), but have discovered some
> discrepancies.  I would like to use PROJ.4 to verify one or the other.
> How can this be done in PROJ.4?

I had a similar problem, I think.  I defined a local system relative to
Massachusetts state plane, putting (40,30) in my grid at some SPC
coordinates.  Then I had a rotation - my Y axis was more or less north,
but not really.  (The point was to have a natural coordinate system in a
parking lot.)

I tried to do this in proj by using the oblique mercator projection, but
never succeeded.  I ended up hand-writing the code, since it was just a
rotation and translation from the state plane system.

Rereading your question: are your X and Y axes along the ellipsoid, or
is this a translation of an ECEF system?  I think it would be helpful
for you to be far more precise about what you are doing.
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