[R-sig-Geo] custom focal function on rasterstack

[Jonathan Greenberg]

Ruben:

Give rasterEngine, within the spatial.tools package a whirl.  Here's
the tutorial for it (some things are bit out of date, but this does
cover the focal analyses):

http://publish.illinois.edu/jgrn/software-and-datasets/rasterengine-tutorial/

Note there are examples of focal windows towards the end of the
tutorial.  If you use a parallel engine (e.g. sfQuickInit() ) it will
run your process in parallel -- I've found a significant speedup using
focal windows in parallel mode.

--j

On Fri, Mar 14, 2014 at 10:10 AM, Ruben Van De Kerchove
<ruben.vandekerchove at gmail.com> wrote:
> Hi,
>
> I have rasterstack consisting out of 252 rasters (hyperspectral image) for
> which I want to calculate the mean distance to the centroid in a 3*3(*252)
> moving window. As the focal function (from the raster package) only works
> for rasters, I am currently using the getValuesBlock function (in a loop),
> but this seems rather slow. Therefore, I was wondering, if there is a more
> efficient way to tackle this problem.
>
> Best,
> Ruben
>
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>
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-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
Department of Geography and Geographic Information Science
University of Illinois at Urbana-Champaign
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