Reprojected data shifted from correct position

Liz Sanderson
Liz Sanderson
  • Updated

FME Version

  • FME 2015.x

Question

When I reproject my data with FME it appears to be out of position. Why?

Answer

There are three likely causes of the problem...

1) You are including a datum conversion in the reprojection and the grid-shift files used were incorrect. Check the log file. It will include information on what datum shift has taken place (if any) and what grid files were used. Incorrect datum shifts can result in errors of 1 to 100 meters. If you are missing a grid shift file your error may only be in the sub meter range.

2) You are using a coordinate system with the wrong units. This is most likely to occur when confusing the different types of 'foot' unit. See the article on foot measurements in FME.

3) You are using a different (possibly incorrect) version of a coordinate system definition. For example, there are several different definitions of the Dutch RD system, National RD/NAP being the most accurate one.

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