-----Original Message-----
From: r-sig-geo-bounces at stat.math.ethz.ch [mailto:r-sig-geo-bounces at stat.math.ethz.ch] On Behalf Of
Agustin Lobo
Sent: 30 juin 2010 10:13
To: r-sig-geo
Cc: agustin.lobo at ija.csic.es
Subject: [R-sig-Geo] polygonValues (raster): Very slow
Hi!
I'm trying:
eugrd025EFDC <- readOGR(dsn="eugrd025EFDC",layer="eugrd025EFDC")
v <- polygonValues(p=eugrd025EFDC, Br, weights=TRUE)
where
str(eugrd025EFDC,max.level=2)
Formal class 'SpatialPolygonsDataFrame' [package "sp"] with 5 slots
..@ data :'data.frame': 18000 obs. of 5 variables:
..@ polygons :List of 18000
.. .. [list output truncated]
..@ plotOrder : int [1:18000] 17901 17900 17902 17903 17899 17898
17904 17897 17905 17906 ...
..@ bbox : num [1:2, 1:2] 2484331 1314148 6575852 4328780
.. ..- attr(*, "dimnames")=List of 2
..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots
Cells: 13967442
NAs : 0
Min. 0.00
1st Qu. 0.00
Median 0.00
Mean 48.82
3rd Qu. 0.00
Max. 4999.00
so quite large objects.
The problem is that polygonValues() has been running (and not
completed the task) for
more than 2 h on a intel core i7 machine with 16 Gb RAM (Dell
Precision M6500), so a pretty powerful machine.
Is there any way I could speed up this process?
Also, is there anything I could do in order to take better advantage
of the 8 processing threads?
Currently, I see only 1 cpu working for R processes and the rest
remain pretty inactive
Thanks
Agus