Raster Package Crash raster:::terrain

Hello,

I'm getting some strange behavior from the raster package terrain(opt =
'roughness') function.

I have a large (~1GB) digital elevation model in .grd format that was
created from a past R session.  When I load the file in and attempt to
calculate the roughness index, I consistently crash R.

In an attempt to debug, I created a raster file with the same extent,
nrows, ncols, and crs as my actual data, and set random values with the
same min and max.  My system is storing the file in memory rather than
writing to the temporary library.  The terrain(opt = 'roughness') function
sometimes runs with the raster in RAM, but usually doesn't.

Since running from memory doesn't help me with my problem, I've created the
sample script to save the simulated DEM to disk then exit R without saving
the session.  You'll then have to restart R.  The second part of the code
attempts to reload the simulated DEM and calculate roughness, and this
piece of code crashes every time I run it (as it does with my actual data).

Here is my sessionInfo(), and a sample code follows:


R version 3.0.1 (2013-05-16)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United
States.1252
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C

[5] LC_TIME=English_United States.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] raster_2.1-37 sp_1.0-9

loaded via a namespace (and not attached):
[1] grid_3.0.1      lattice_0.20-15


#===============================================================================
#Example code
#Set the working directory to your system
#===============================================================================
setwd('C:/Users/avitale/Documents')
library(raster)

#set the extent, resolution, and crs to match my data
r <- raster(xmn =  688256.5, xmx = 779259.5, ymn = 4276005, ymx = 4396000,
nrows = 11650, ncols = 11347,
crs = "+proj=utm +zone=11 +datum=WGS84 +units=m +no_defs +ellps=WGS84
+towgs84=0,0,0")

set.seed(232)
r[] <- runif(ncell(r), min = 1352, max = 3981)

#Write r to disk and exit the r session without saving
r <- writeRaster(r, 'r_from_File.grd', overwrite = TRUE)
q(save = 'no')

#===============================================================================
#Restart R!!!
#Set the working directory to your system
#===============================================================================
setwd('C:/Users/avitale/Documents')
library(raster)

r <- raster(file.path(getwd(), 'r_from_File.grd'))
rough <- terrain(r, opt = 'roughness', filename = 'roughness_test.grd',
overwrite = TRUE)



--
*Andrew P. Vitale*
Masters Student
Department of Geography
University of Nevada, Reno
(412) 915-3632
vitale232 at gmail.com

        [[alternative HTML version deleted]]