[R-sig-Geo] working with large ascii files in R

[Robert J. Hijmans]

Rocio,

You should not use functions read.asc and raster.from.asc because they
read all the values into memory. Also please indicated which packages
you use. The below should fix the problem:

setwd('G:/future_A2a/2020/bccr_bcm2_0_sres_a2_2020s/')
library(raster)
mask<-raster("C:/xalapa/worldclim_pres/bio01.asc")
files <- list.files(pattern='\\.asc$')
s <- stack(files)
x <- crop(s, mask)

And it would indeed good to use a current version of R and its packages.
Robert


On Thu, Jul 18, 2013 at 12:05 AM, Rocio Ponce <r.ponce.reyes at gmail.com> wrote:
> Hi there,
> I'm a newie in using R to make maps... I used to work with ArcGis but I ran
> out of a valid license...
>
> I'm trying to crop the future Worldclim datasets layers which are huge
> ascii files (of the whole world at 1km resolution, so they are between
> 3-4GB each)  to the extent of Mexico using the library (raster).
>
> I used the following code:
>
>>setwd('G:/future_A2a/2020/bccr_bcm2_0_sres_a2_2020s/')
>>maask<-  read.asc("C:/xalapa/worldclim_pres/bio01.asc",gz=FALSE)
>>mask<-raster.from.asc(maask,projs=NA)
>>files <- list.files(pattern='\\.asc$')
>>s <- stack(files)
>> crop(s, mask)
> Error: cannot allocate vector of size 253.2 Mb
>
>
> I'm using R.2.14.1 on a computer running on Windows XP
> Any help that you could provide me would be greatly appreciated,
>
> Cheers,
> Rocio
>
> --
> Dr. Rocio Ponce-Reyes
>
> http://rocioponcereyes.wordpress.com/
>
> (disculpe la falta de acentos en este correo electronico)
>
>         [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo