[FWTools] gdal_merge for 174 images :realy impossible ?

Wolfgang Zillig wollez at gmx.net
Mon Oct 29 11:16:07 EDT 2007

cocro schrieb:
> Hello, 
> I wish to aggregate 174 georeferences jpg images of 10 Mb each there only
> one image.
> I launched the command gdal_merge on my directory but I do not obtain the
> expected result
> I made out a will with three iamges, formulae of aggregation and it works.
> ( Gdal_merge-o MesDalles.jpg co TFW=YES dalle1.jpg dalle2.jpg dalle3.jpg) 
> Gdal_merge is it limited in numbers of images in entrance and\or in sizes
> images? Is it limited for embellish with images it destination?
> How may I resolve my problem? 
> Then, I have to cut my image result according to the outlines of my 64
> polygons (shape)
> Thanks for your help
> Corinne
there are limits in command line string length and the number of open 
files, but these depend on the OS.
Gdal_merge creates a tiff and converts to other file types afterwards. 
You should try to create a tiled tiff (better for memory) with -co 
"TILED=YES". Roughly your final image will have around 1.7 Gb as jpeg, 
uncompressen tiff will be much bigger! So you have to look for bigtiff 
option, but I'm not sure if that is supportet by gdal_merge.


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