An output grid created by PROJECTGRID with the NINE or SEVENTEEN options can be substantially larger than the input grid.
This is a known problem with the internal grid compression scheme for these outputs.
This problem doesn't occur with PROJECT and PROJECTGRID with the FULL option.
Grid: grd_project = projectgrid (grd_source, prj_file.prj, #, nine)
Grid: setwindow grd_project
Grid: setcell grd_project
Grid: grd_resamp = resample (grd_project)