[gdal-dev] Output format in using gdal_translate

[Frank Warmerdam]

Limei Ran wrote:
> 
> Hi,
> 
> Thanks for all your help on using gdal_translate.  I was successful on 
> creating a huge image with -of HFA.  I still have two questions about 
> raster formats used in GDAL:
> 
> 1. The utility created three output files:
> out.ige, out.img, out.img.aux.xml.  What is .ige file (it is a huge file 
> --  close to 12gb) since my input has only two files with .img and .rrd?

Limei,

The .ige file is the image overflow file and is used to hold image data
larger than 2GB.

> 2. I am creating a raster file for some calculation.  So, formats do not 
> matter as long as it is efficient in storing and accessing. Is any GDAL 
> raster format with no Limit Size (such as ESRI .hdr Labelled) better 
> than HFA format in storing and accessing?

HFA format should be of comparible performance to other large file formats,
and in particular should provide good performance when selecting a subwindow
due to the tiling used.  ESRI .hdr labelled should also be similarly fast
for scanline by scanline access, but will have poorer performance if you
only try to access a subwindow area.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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