[Gdal-dev] mean value of rasters

[Christopher Condit]

I tried in R and came very close.  My script looked something like this
(just to make sure things were working):

library(rgdal)
ds <- GDAL.open("C:/path/test.tif")
vals <- getRasterData(ds)
GDAL.close(ds)
write.table(vals, "C:/path/out.txt")

But when I look at that file as an ASCII grid (which makes sense to do,
right?) my original image is rotated 90 degrees and doubled.
Am I missing something about the rgdal component?  Seems that it should
have worked...

Thanks,

Chris


-----Original Message-----
From: Frank Warmerdam [mailto:fwarmerdam at gmail.com] On Behalf Of Frank
Warmerdam
Sent: Thursday, May 04, 2006 1:00 PM
To: Christopher Condit
Cc: Gdal-dev at lists.maptools.org
Subject: Re: [Gdal-dev] mean value of rasters

Christopher Condit wrote:
> I've got N raster files (GeoTiffs) of equal size and dimensions.  I'd
> like to create a single raster with the mean value of these N rasters
> (cell by cell).  Is there a good way to do this with GDAL, or with
> another tool?  

Chris,

There is not direct way of doing this with the commandline utilities.
It would be relatively easy to implement using Python bindings for
GDAL and Numerical Python.  I imagine this could also be done in
something
like R or GRASS relatively directly.

Best regards,
-- 
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