[gdal-dev] losing elevation data

[Devrim Baris Acar]

Hi,
I am a newbie on gdal and gis so forgive me.

I have downloaded the geotiff elevation data  srtm30.7z from
http://worldwind28.arc.nasa.gov/public/WorldWindWMS/ . The file contains
elevation data for the globe. I want to change a a geotiff file from this
set to bil file format(hoping to use it in worldwind).

I use;

gdal_translate -of EHdr e020n40.Bathmetry.tif deneme.bil

It completes translation with no errors but when I open the file in free
tool ER Viewer it is pure black and white while the original contains tones
of gray.
It seems to have loss the granularity of data.

Why does this happen?
Thanks.
-- 
Devrim Baris Acar
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