[gdal-dev] gdal_merge output JPG unable to write

[Doug_Newcomb at fws.gov]

Basker,

You might also want to look at  http://www.gdal.org/formats_list.html.  The
last column lists the Maximum file size.  If you are merging multiple 2 GB
files, you will hit the 4 GiB limit for the standard JPEG format  fairly
quickly.

Doug

Doug Newcomb
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_newcomb at fws.gov
---------------------------------------------------------------------------------------------------------

The opinions I express are my own and are not representative of the
official policy of the U.S.Fish and Wildlife Service or Dept. of Interior.
Life is too short for undocumented, proprietary data formats.


                                                                           
             Frank Warmerdam                                               
             <warmerdam at pobox.                                             
             com>                                                       To 
             Sent by:                  SriRam Prasad Bhasker               
             gdal-dev-bounces@         <SriRam.PrasadBhasker at rmsi.com>     
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                                       gdal-dev at lists.osgeo.org            
                                                                   Subject 
             01/22/2008 09:53          Re: [gdal-dev] gdal_merge output    
             AM                        JPG unable to write                 
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




SriRam Prasad Bhasker wrote:
>
> Hi
>
> Gdal_Merge is not supporting JPEG Driver for Writing..
>
> can anyone one know list of valid output drivers for Gdal_merge
>
> I have 2.0 Gb sized Jpeg Files (150 odd..)need to merge them into one
> Mosaiced Jpeg File.

Bhasker,

If you do "gdal_merge.py --formats" it will list all the formats supported
by the current build.  All those with "rw+" in brackets afterwards are
suitable output formats.  If they have "ro" then the format is read only.
If they have "rw" then the format supports writing, but only in "copy in
a single pass from another dataset" mode which is insufficient for
gdal_merge.py which needs to write the output in somewhat random chunks.

Note that you can merge into a mosaic in a format like Erdas Imagine or
BigTIFF (if you are using a new enough build) and then gdal_translate that
to JPEG.  I would however stress that JPEG is a poorly performing format
for large geospatial datasets that you want to access randomly in a
desktop viewer or web mapping situation for instance.

Best regards,
--
---------------------------------------+--------------------------------------

I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org

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