(This article was first published on

**Quantitative Ecology**, and kindly contributed to R-bloggers)This is how to use the Pixmap library to read in an image as a matrix.

> library(pixmap)

# the next command may only work on Linux

> system("convert foo.tiff foo.ppm")

> img <- read.pnm("foo.ppm")

To get info on your new object:

> str(img)

Although included in the previous output, the size of the image can be extracted by:

>img@size

Then to extract the red channel from the image for the first ten rows:

> myextract <- img@red[1:10,]

Or to extract the entire red channel to an actual matrix:

> red.mat<-matrix(NA,img@size[1],img@size[2])

> red.mat<-img@red

To

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