Question

FME uses a lot of disk space when writing to ECW, much more than the size of the source data. Why?

Answer

The expected behavior is for the uncompressed data to be written to disk before the compressed ECW is written. Unfortunately there is currently no way to avoid this based on the underlying library that is used. We suggest setting FME_TEMP to a location where more disk space is available (say an external hard drive or network resource).