[gdal-dev] gdaladdo without explicit factors specified

Even Rouault even.rouault at spatialys.com
Wed Jun 28 05:10:17 PDT 2017


I'm pretty sure this must have annoyed a lot of people. When you run gdaladdo, you need to 
specify the appropriate overview levels. Generally you use power-of-two factors, but the 
question is then: what is the last relevant factor given the dimension of my file size ? 

I've a ready to commit improvement where you can just do :
gdaladdo [other options] my.tif
and it will compute the appropriate power of two factors until the smallest overview is 
smaller or equal to 256x256 (this threshould can be adjusted with a new -minsize switch. 
Actually it should be named -maxminsize, since this is the maximum size of the smallest 
overview, but I guess -minsize will be clear enough)

The effect of this patch is the same as specifying manually all the overview factors implicitly 
computed. That means existing overview levels will be recomputed if their factor match one 
of the implicitly computed factors. Or they will be left unchanged if not matching one of the 
implictly computed overview factors.

Thoughts ?


Spatialys - Geospatial professional services
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