Hi Jacob,
Thanks for the suggestion. So...
func <- function(X) {x <- movingFun(c(X), n=3, sum, 'from',
circular=TRUE);return(x)}
mon_stac <- stack(paste(pc_clim,"",y,"_prec",1:12,".asc", sep=""))
# then
wetness_quarters <- calc(mon_stac, func)
Error in .local(x, fun, ...) : function 'fun' returns more than one value
# This make sense that this would do this..
# Now this to get the first month of the max quarter by returning first
month number:
func <- function(X) {x <- which.max(movingFun(c(X), n=3, sum, 'from',
circular=TRUE));return(x)}
# Then
wetness_quarters <- calc(mon_stac, func)
Error in v[, tr$row[i]:(tr$row[i] + tr$nrows[i] - 1)] <- matrix(sv, nrow
= ncol(outraster)) :
incorrect number of subscripts on matrix
# This error being returned after a long time busying a quadcore computer...
Even if I can get your suggestion to work, I am still faced with the
problem of retrieving the sum of values of the quarter marked my the
month number,
which should look something like this:
quart_value <- function(a,b,d,e,f,g,i,j,k,l,m,n,o){
ifelse(o==1, X <- mean(c(a,b,d)),
ifelse(o==2, X <- mean(c(b,d,e)),
ifelse(o==3, X <- mean(c(d,e,f)),
ifelse(o==4, X <- mean(c(e,f,g)),
ifelse(o==5, X <- mean(c(f,g,i)),
ifelse(o==6, X <- mean(c(g,i,j)),
ifelse(o==7, X <- mean(c(i,j,k)),
ifelse(o==8, X <- mean(c(j,k,l)),
ifelse(o==9, X <- mean(c(k,l,m)),
ifelse(o==10, X <- mean(c(l,m,n)),
ifelse(o==11, X <- mean(c(m,n,a)),
ifelse(o==12, X <- mean(c(n,a,b)),NA))))))))))))
return(X)}
#For BIO8
mon_stac.wq <- stack(paste(pc_clim,"",y,"_tmean",1:12,".asc", sep=""),
wetness_quarters)
tmean.wq <- overlay(mon_stac.wq, fun=quart_value)
With "o" being the product of the "func"or "maxmonth" function
I think that I NEED to get the "overlay" function to work, but am of
course open to suggestions.
I appreciate the help.
Regards,
Brian
On 11/8/2010 10:59 AM, Jacob van Etten wrote:
> I don´t know what the problem is with overlay(), but you could use an
> alternative approach, using calc() instead.
>
> Something like this (not tried)
>
> library(raster)
> library(dismo)
> func <- function(x, ...) movingFun(x, n=3, sum, circular=TRUE)
> wetness_quarters <- calc(mon_stac, func)
> wettest_quarter <- calc(wetness_quarters, function(x) which(x == max(x))
>
> The output input should indicate the month in the centre of the
> wettest quarter.
>
> Jacob.
>
> --- On *Mon, 8/11/10, Brian Oney /<zenli...@gmail.com>/* wrote:
>
>
> From: Brian Oney <zenli...@gmail.com>
> Subject: [R-sig-Geo] Bioclimatic variables - wettest quarter
> To: r-sig-geo@stat.math.ethz.ch
> Date: Monday, 8 November, 2010, 1:40
>
> Hello All,
>
> I am attempting to reproduce the bioclimatic (Worldclim, Hijmans et al
> 2005) variables with the raster package and I am stuck on the group
> "temp of driest quarter" etc. variables.
> I am attempting it with the function "overlay" ("raster" package).
>
> Here is how it looks:
> # To know the first month of the wettest quarter
> maxmonth<- function(a,b,d,e,f,g,i,j,k,l,m,n){
> o<- sum(c(a,b,d))
> p<- sum(c(b,d,e))
> r<- sum(c(d,e,f))
> u<- sum(c(e,f,g))
> v<- sum(c(f,g,i))
> w<- sum(c(g,i,j))
> x<- sum(c(i,j,k))
> y<- sum(c(j,k,l))
> z<- sum(c(k,l,m))
> aa<- sum(c(l,m,n))
> ab<- sum(c(m,n,a))
> ac<- sum(c(n,a,b))
> ad<- which.max(c(o,p,r,u,v,w,x,y,z,aa,ab,ac))
> return(ad)}
> >
> maxmonth(a=13,b=16,d=41,e=61,f=41,g=16,i=15,j=14,k=13,l=11,m=31,n=11)
> # works: 2nd element (month) is the beginning of the wettest quarter
> [1] 2
> mon_stac<- stack(paste(pc_clim,"",y,"_prec",1:12,".asc", sep=""))
> # Now attempt it
> avg<- overlay(mon_stac, fun=maxmonth)
> Error in .overlayList(rasters, fun = fun, filename = filename, ...) :
> cannot use this formula; lenghts do not match
>
> # How about manually?
> a<- raster(paste(pc_clim,"",y,"_prec",1,".asc", sep=""))
> b<- raster(paste(pc_clim,"",y,"_prec",2,".asc", sep=""))
> d<- raster(paste(pc_clim,"",y,"_prec",3,".asc", sep=""))
> e<- raster(paste(pc_clim,"",y,"_prec",4,".asc", sep=""))
> f<- raster(paste(pc_clim,"",y,"_prec",5,".asc", sep=""))
> g<- raster(paste(pc_clim,"",y,"_prec",6,".asc", sep=""))
> i<- raster(paste(pc_clim,"",y,"_prec",7,".asc", sep=""))
> j<- raster(paste(pc_clim,"",y,"_prec",8,".asc", sep=""))
> k<- raster(paste(pc_clim,"",y,"_prec",9,".asc", sep=""))
> l<- raster(paste(pc_clim,"",y,"_prec",10,".asc", sep=""))
> m<- raster(paste(pc_clim,"",y,"_prec",11,".asc", sep=""))
> n<- raster(paste(pc_clim,"",y,"_prec",12,".asc", sep=""))
>
> avg<- overlay(a,b,d,e,f,g,i,j,k,l,m,n, fun=maxmonth)
> Error in .overlayList(rasters, fun = fun, filename = filename,
> datatype
> = datatype, :
> cannot use this formula; lenghts do not match
>
> Also doesn't work...
> > length(mon_stac[1])
> [1] 12
> I have 12 rasters being fed into overlay, but it won't buy it.
> I think that my first step is to know the first month of the wettest
> month. Once I can do that I can do it for temperature as well.
>
> Thanks and Regards,
> Brian
>
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