[R-sig-Geo] Error with function kfold in package dismo

[Robert J. Hijmans]

Manuel,

This looks like a bug in 'raster' that I think I have fixed in version
1.5-13 (should be available on R-Forge in 24 hrs or so).

As a work around, you can save ascii files to binary (once):

predictores <- writeRaster(predictores, 'predictores.grd' )
# or
predictores <- writeRaster(predictores, 'predictores.tif' )

and then in the script use:

predictores <- brick('predictores.grd')
# or
predictores <- brick('predictores.tif')


This also has the advantage of being much faster.

Robert

On Sat, Oct 2, 2010 at 3:11 PM, Manuel Spínola <mspinola10 at gmail.com> wrote:
>  Dear list members,
>
> I got this error in package "dismo".
>
> fold <- kfold(bradypus, k=5)
>> bradytrain <- bradypus[fold != 1, ]
>> me <- maxent(predictores, bradytrain)
> Error en .readRowsAscii(raster, rows[i], 1) : elemento 1 esta vacio;
>  la parte de la lista de argumentos  '>' ha sido evaluada:
>   (startcol, 1)
>
> Function maxent works perfect for "bradypus" (data frame with 116
> observations), but it doesn't work for "bradytrain" when I use kfold
> function.
> "bradytrain" is also a data frame but with 93 observations.  The message is
> in Sapnish, but basically say that element 1 is empty.
>  Thank you very much in advance.
>  Best,
>
> Manuel
>
> --
> Manuel Spínola, Ph.D.
> Instituto Internacional en Conservación y Manejo de Vida Silvestre
> Universidad Nacional
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