[R-sig-Geo] Unable to use factors in raster::predict

[Gonzalez-Mirelis, Genoveva]

Dear list,

I would like to use the 'predict' function in the 'raster' package in an implementation of species distribution modelling with a couple of factor variables. My case can be set up exactly as the cforest example listed in the help file. Unfortunately, I cannot get the example to work: it throws an error because of the unused argument 'factors', which I need. Here is the code I am referring to:

# create a RasterStack or RasterBrick with with a set of predictor layers
logo <- brick(system.file("external/rlogo.grd", package="raster"))
names(logo)

# known presence and absence points
p <- matrix(c(48, 48, 48, 53, 50, 46, 54, 70, 84, 85, 74, 84, 95, 85,
              66, 42, 26, 4, 19, 17, 7, 14, 26, 29, 39, 45, 51, 56, 46, 38, 31,
              22, 34, 60, 70, 73, 63, 46, 43, 28), ncol=2)

a <- matrix(c(22, 33, 64, 85, 92, 94, 59, 27, 30, 64, 60, 33, 31, 9,
              99, 67, 15, 5, 4, 30, 8, 37, 42, 27, 19, 69, 60, 73, 3, 5, 21,
              37, 52, 70, 74, 9, 13, 4, 17, 47), ncol=2)

# extract values for points
xy <- rbind(cbind(1, p), cbind(0, a))
v <- data.frame(cbind(pa=xy[,1], extract(logo, xy[,2:3])))

# cforest (other Random Forest implementation) example with factors argument

v$red <- as.factor(round(v$red/100))
logo$red <- round(logo[[1]]/100)

library(party)
m <- cforest(pa~., control=cforest_unbiased(mtry=3), data=v)
f <- list(levels(v$red))
names(f) <- 'red'
pc <- predict( m,logo, OOB=TRUE, factors=f)

Error in RET using prediction_weights(newdata = newdata, mincriterion = mincriterion,  :
  unused argument (factors = f)


Note that I needed to change the order in the arguments in the last line. If I run it the way it was in the example, like this:

pc <- predict(logo, m, OOB=TRUE, factors=f)


then the error is the following:


Error in v[cells, ] <- predv :

  number of items to replace is not a multiple of replacement length

Also note that if I run the line without the 'factors' argument the resulting value (r) is a matrix, and not a raster object.

I am using Package 'raster' version 2.6-7 on Windows 7 (where this worked fine in the past).

Many thanks for any help,

Genoveva

Genoveva Gonzalez Mirelis, Scientist
Institute of Marine Research
Nordnesgaten 50
5005 Bergen, Norway
Phone number +47 55238510


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