Also, regarding changing resolutions, you might want to check out this
vignette: http://cran.r-project.org/web/packages/raster/vignettes/Raster.pdf
In particular, see section 5.1, starting on page 12.
Cheers,
mike
On Mon, Oct 21, 2013 at 11:25 PM, Michael Treglia <mtreg...@gmail.com>wrote:
> Manuel,
>
> Given that your layers also have different resolutions, I think you need
> to use resample(). Since you need to set the resolutions the same to stack
> the rasters, give it some thought to make sure you are doing what your
> really want - which resolution is more appropriate and such, and which
> resampling procedure makes the most sense.
>
> This is assuming your two layers are in the same projection (in your
> dataset, it looks like the projection for 'distpob_b' is not set). If your
> layer 'distpob_b' is in the same projection as 'forestRaster', you can make
> sure the projection is set the same by using:
> projection(distpob_b) <- projection(forestRaster)
>
> Then, use resample() to make them the same resolution and dimensions:
> distpobResamp <- resample(distpob_b, forestRaster, resample='bilinear') #
> I set it so the result would be the same size as the layer with the smaller
> extent
>
> s<-stack(distpobResamp, forestRaster) #creates stack, 's'
>
> If the projections are different, you can first set the projection of
> distpob_b using the projection() <- command, and then use projectRaster to
> transform it so they are in the same projection, and you can simultaneously
> resample them/set the same resolution. Again, think about which
> reprojection is best, and if you're dealing with lots of layers, it may be
> best to us the most common projection, as to avoid errors caused by
> resampling.
>
>
> Here's a full example with made-up data, but using the same
> resolutions/extents as your data:
>
>
> library(raster)
>
> ##Create raster 'r1' (same dimensions and resolution as distpob_b)
> r1 <- raster(xmn=447181, xmx=517981, ymn=1121851, ymx=1216051,
> crs=CRS('+proj=tmerc +lat_0=0 +lon_0=-84 +k=0.9999 +x_0=500000 +y_0=0'))#
> res=300)
> res(r1) <- 300
> values(r1) <- runif(ncell(r1)) #Fill with values
> #plot(r1)
>
> ##Create raster 'r2' (same dimensions and resolutoin as forestRaster)
> r2 <- raster(xmn=447235.4, xmx=517235.4, ymn=1122046, ymx=1216046,
> crs=CRS('+proj=tmerc +lat_0=0 +lon_0=-84 +k=0.9999 +x_0=500000 +y_0=0'))
> res(r2) <- 500
> values(r2) <- runif(ncell(r2))
> #plot(r2)
>
> ##Resample r1 to extent/resolution of r2
> r1rsmp <- resample(r1,r2, resample='bilinear')
>
> ##Create stack 'r1r2stk'
> r1r2stk <- stack(r1rsmp, r2)
>
> ##Plot them to make sure it looks right...
> #plot(r1r2stk)
>
> Hope that helps,
> Mike
>
>
>
>
> On Mon, Oct 21, 2013 at 4:11 PM, Manuel Spínola <mspinol...@gmail.com>wrote:
>
>> Dear list members,
>>
>> I am trying to stack 2 rasters, but I got an error:
>>
>> > nd <- stack(forestRaster, distpob_b)
>> Error in compareRaster(x) : different extent
>>
>> > show(forestRaster)
>> class : RasterLayer
>> dimensions : 188, 140, 26320 (nrow, ncol, ncell)
>> resolution : 500, 500 (x, y)
>> extent : 447235.4, 517235.4, 1122046, 1216046 (xmin, xmax, ymin,
>> ymax)
>> coord. ref. : +proj=tmerc +lat_0=0 +lon_0=-84 +k=0.9999 +x_0=500000 +y_0=0
>> +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0
>> data source : in memory
>> names : layer
>> values : 0, 100 (min, max)
>>
>> > show(distpob_b)
>> class : RasterLayer
>> dimensions : 314, 236, 74104 (nrow, ncol, ncell)
>> resolution : 300, 300 (x, y)
>> extent : 447181, 517981, 1121851, 1216051 (xmin, xmax, ymin, ymax)
>> coord. ref. : NA
>> data source : in memory
>> names : layer
>> values : 5.644242, 9530.715 (min, max)
>>
>>
>> How I make 2 raster with equal extent?
>>
>> Best,
>>
>> Manuel
>>
>> --
>> *Manuel Spínola, Ph.D.*
>> Instituto Internacional en Conservación y Manejo de Vida Silvestre
>> Universidad Nacional
>> Apartado 1350-3000
>> Heredia
>> COSTA RICA
>> mspin...@una.ac.cr
>> mspinol...@gmail.com
>> Teléfono: (506) 2277-3598
>> Fax: (506) 2237-7036
>> Personal website: Lobito de río <
>> https://sites.google.com/site/lobitoderio/>
>> Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>
>>
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>>
>>
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>>
>
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