[ferret_users] question about binary file writing in ferret: doubling of size with repeat

[Lev Tarasov <lev@xxxxxx>]

Hi all;
	to facilitate reuse of some old code, I needed to convert
a netcdf DEM to binary, with sequential records for each latitude (and 
colatitude ordering):
ie:
set region /J=10801
LIST /FORMAT=UNF/FILE=GEBCO_2D_1min.bincollatrec ELEVATION
can region
repeat /J=10800:1:-1 LIST /FORMAT=UNF/APP/FILE=GEBCO_2D_1min.bincollatrec ELEVATION

this gave
-rw-r----- 1 3732998416 Jan 19 10:50 GEBCO_2D_1min.bincollatrec

This nearly doubled the size of the file compared to simply
LIST /FORMAT=UNF/FILE=GEBCO_2D_1min.bin ELEVATION

-rw-r----- 1 1866585616 Jan 19 09:04 GEBCO_2D_1min.bin

Why the doubling?

Cheers,

Lev

Lev Tarasov -   Dept of Physics and Physical Oceanography,
		Memorial University of Newfoundland.
                email: lev@xxxxxx
                http://www.physics.mun.ca/~lev/
		Tel (709)-864-2675
		Fax (709)-864-8739