[Qgis-developer] [Qgis-user] Pyramids and Virtual maps - technical details

[Mayeul Kauffmann]

Le dimanche 11 mars 2012 à 16:31 +0200, Zirneklitis a écrit :
> Hi,
> 
> I have many raster maps (size 2000x2000 pixels). I have created a 
> virtual dataset including all of them.
> 
> The first question: what pyramids should be built?
> 
> 1. Large scale pyramids (e.g. 2 and 8 (in terms of gdaladdo) for each 
> raster map separately and small scale pyramids (e.g. 16 and 32) for the 
> Virtual data set.
> 
> OR
> 
> 2. Full set of pyramids for the Virtual data set.
I have used this option with a large vrt made of 256x256 png tiles
without any issue. Probably the easiest to do ( a few clicks). Then
performant wise, maybe you have to try both.

Mayeul 


> 
> 
> The second question:  Is it reasonable to make only every second pyramid 
> (e.g. 4, 16, 64)? - performance/disk waste issue.
> 
> Thank You,
> Karlis
> 
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