CODEWITHSUNDEEP
rraster
wesleysc352
wesleysc352

Reputation: 617

Reclassify raster with multiple ranges in R

I have a raster and I would like to reclassify its values ​​to four values ​​(NA, 1, 2 and 3).

I used the reclassify command from the raster package. In this command it is possible to indicate an array containing the intervals that must be reclassified. But it seems to me that reclassify only accepts a 3x3 array, so I can't reclassify more than 3 ranges.

I tried to assign an array m containing all my ranges to the rcl within the reclassify command, but it only considers the first 3 rows, so the other rows of the array are ignored by the command.

the m array works like this:

the first column represents the lower value range, the second column represents the upper value range, and the third column represents the new value assigned to that cell. For example, in the line at line 1 0,0,NA I want all values ​​equal to zero to be converted to NA. On line 2 1,5,1, I want all values ​​between 1 and 5 to be converted to value 1. On 7th line 16,19,3 for example, values ​​between 16 and 19 should be converted to value equal to 3, and so on.

I don't know what's wrong with this conversion. Would I accept a solution with a raster package or another package?

a exemple here

#raster
r <- raster(matrix(runif(100, 0, 50), ncol=10))
plot(r)

enter image description here

#matrix with rules reclass
m<-matrix(c(0,0,NA,
            1,5,1,
            6,8,3,
            9,9,2,
            10,13,1,
            14,15,2,
            16,19,3,
            20,20,2,
            21,23,3,
            24,24,3,
            25,25,3,
            26,32,3,
            33,33,3,
            34,38,3,
            39,39,2,
            40,40,3,
            41,41,2,
            42,Inf,3), ncol=3, byrow=TRUE)

#r2 with reclass
r2<-raster::reclassify(x=r, rcl=m)

Upvotes: 0

Views: 1211

Answers (1)

Robert Hijmans
Robert Hijmans

Reputation: 47146

It works better if there are no gaps in the reclassification matrix

#matrix with rules reclass
m<-matrix(c(0,1,NA,
            1,6,1,
            6,8,3,
            8,9,2,
            9,13,1,
            13,15,2,
            15,19,3,
            19,20,2,
            20,23,3,
            23,24,3,
            24,25,3,
            25,32,3,
            32,33,3,
            33,38,3,
            38,39,2,
            39,40,3,
            40,41,2,
            41,Inf,3), ncol=3, byrow=TRUE)

#r2 with reclass
r2<-raster::reclassify(x=r, rcl=m, include.lowest=TRUE)

This has to be done like that with decimal numbers. With integers, it could be allowed to specify it the way you want think about it, where the interval is open at both sides, and from and to can be the same value, but that is currently not the case.

Upvotes: 1

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