Question

Reprojecton difference 64 bit engine vs 32 bit

  • 11 April 2019
  • 1 reply
  • 2 views

Badge +4

FME Server 2018, running distributed engines, mix of 32 bit and 64 bit. What I am seeing is that the some features when reprojected (using ESRI Reprojector NAD83 to North_America_Albers_Equal_Area_Conic or using the FME Reprojector Read from feature (ll-83) to say UT83-N for example, a few of the resulting coordinates are different about the 9th decimal place (from what i have seen only the Y coord gets tweaked) . Not enough to really mean anything, but enough to cause a different CRC value or for the ChangeDetector to see them as different. Any thoughts on why 64 bit Engine might result in very slightly different coordinate values ?


1 reply

Userlevel 4

Just a theory, but it's possible that the 32-bit version uses single precision floats internally, where as the 64 bit version might use double precision floats for the calculations.

Single precsion floats have a precision to about 7 or 8 decimals, which could explain what you're observing.

You may want to retry using FME 2019, I believe some aspects of the EsriReprojector has been redone.

Reply