我有一个dem图，想把它转成spatstat中的pixel image的im格式
用raster包
>r1 = raster("D:/SpeceisCompostion/New Folder/demxiao")
> M<-as.matrix(r1)
> P<-im(M,xcol=2971,yrow=2621)
Error in im(M, xcol = 2971, yrow = 2621) :
  Length of xcol does not match ncol(mat)
报错如上，，


我把dem图转成ascii格式，用R读在转换，
Z<-read.table("E:\\demasc.txt",header=F,sep=" ")
ZZ<-matrix(Z,nrow=2621,ncol=2971,byrow=F)

P<-im(ZZ,xcol=2971,yrow=2621)
Error in im(ZZ, xcol = 2971, yrow = 2621) :
  Length of xcol does not match ncol(mat)


又报同样的错，，我想知道这是哪块出了问题啊，，
数据的nrows=2621，ncols=2971