[R] Speeding up image plots

Maik Heistermann maik.heistermann at uni-potsdam.de
Mon Oct 1 11:27:11 CEST 2007

Dear R-users,

I wonder whether it is possible to speed up plots of 2-dimensional 
images (such as image() or levelplot()) in order to export lower quality 
versions of the resulting plots.

I intend to export a large number of images in order to construct 
animated gifs. For this purpose, I used the png()-function in 
conncection with image() and levelplot(). But the underlying arrays are 
so big (900x900 entries) that the export of every single image takes 
very long. Using caTools for exporting animated gifs from 3-dimensional 
arrays (dim(array)=c(900,900,No of plots) works extremely fast, but 
unfortunately, the level of flexibility for plot design is very low (no 
labelling, legends etc.).

I guess the problem is that levelplot() or image() first plot a full 
quality image. Only on export, the quality settings from png() or jpeg() 
(e.g. for resolution) become effective. How could I provide quality 
settings before the time consuming plotting process starts?

Thanks a lot in advance for any kind of help!

Best regards,

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