[GRASS-user] Natural breaks classification

[Luigi Ponti]

On 16/05/2012 20:55, Salvatore Mellino wrote:
> I'm trying but I receive an error.
>
> 1. In R I started the libraries spgarass6 and classInt
> 2. I imported the DTM in R using           DTM<- readRAST6("DTM at mapset", ignore.stderr=TRUE)
> 3. I used the command                DTM_class<- classIntervals(DTM, n=5, style="fisher")             and I received the error
>
> Error in classIntervals(DTM, n = 5, style = "fisher") :
>    var is not numeric

I do not recall exactly, but it may be that classIntervals does not have 
a method for spatial data frames (i.e. the output of readRAST6). One 
thing I would try to get the breaks anyway, is a regular R data.frame, 
for example:

DTM.df <- as.data.frame(DTM)
DTM_class <- classIntervals(DTM.df, n=5, style="fisher")

Hope this helps,

Luigi