# Replace.im

0th

Percentile

##### Reset Values in Subset of Image

Reset the values in a subset of a pixel image.

Keywords
manip, spatial
##### Usage
## S3 method for class 'im':
[(x, i) <- value
##### Arguments
x
A two-dimensional pixel image. An object of class "im".
i
Object defining the subregion or subset to be extracted. Either a spatial window (an object of class "owin") or a point pattern (an object of class "ppp") or something that can be converted into a point pattern by
value
Vector of replacement values (short vectors will be recycled).
##### Details

This function changes some of the pixel values in a pixel image. The image X must be an object of class "im" representing a pixel image defined inside a rectangle in two-dimensional space (see im.object).

The subset to be changed is determined by the argument i.

If i is a spatial window (an object of class "owin"), the values of the image inside this window are changed.

If i is a point pattern (an object of class "ppp", or something that can be converted into a point pattern by as.ppp), then the values of the pixel image at the points of this pattern are changed.

If i does not satisfy any of the conditions above, then it is assumed to be a valid index for the matrix as.matrix(x).

##### Value

• The image x with the values replaced.

• [<-.im
##### Examples
# make up an image
X <- setcov(unit.square())
plot(X)

# a rectangular subset
W <- owin(c(0,0.5),c(0.2,0.8))
X[W] <- 2
plot(X)

# a polygonal subset
data(letterR)
R <- affine(letterR, diag(c(1,1)/2), c(-2,-0.7))
X[R] <- 3
plot(X)

# a point pattern
P <- rpoispp(20)
X[P] <- 10
plot(X)

# change pixel value at a specific location
X[list(x=0.1,y=0.2)] <- 7
Documentation reproduced from package spatstat, version 1.19-2, License: GPL (>= 2)

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