FME raster features represent raster data and use several concepts that are unlike those used in the handling of vector data. See About FME Rasters.
Z-Map Grid files can be written with non-square pixel dimensions.
Z-Map Grid only supports rasters with a single band. Z-Map Grid does not support palettes or Ground Control Points. The Z-Map Grid writer will warn about the presence of Ground Control Points. It is an error if palettes or multiple bands are present in the input feature.
Z-Map Grid does not support rotation; therefore, if rotation is present, it is applied to the output data as an affine transformation.