nearest.raster.point

0th

Percentile

Find Pixel Nearest to a Given Point

Given cartesian coordinates, find the nearest pixel.

Keywords
manip, spatial
Usage
nearest.raster.point(x,y,w, indices=TRUE)
Arguments
x
Numeric vector of $x$ coordinates of any points
y
Numeric vector of $y$ coordinates of any points
w
An image (object of class "im") or a binary mask window (an object of class "owin" of type "mask").
indices
Logical flag indicating whether to return the row and column indices, or the actual $x,y$ coordinates.
Details

The argument w should be either a pixel image (object of class "im") or a window (an object of class "owin", see owin.object for details) of type "mask".

The arguments x and y should be numeric vectors of equal length. They are interpreted as the coordinates of points in space. For each point (x[i], y[i]), the function finds the nearest pixel in the grid of pixels for w.

If indices=TRUE, this function returns a list containing two vectors rr and cc giving row and column positions (in the image matrix). For the location (x[i],y[i]) the nearest pixel is at row rr[i] and column cc[i] of the image.

If indices=FALSE, the function returns a list containing two vectors x and y giving the actual coordinates of the pixels.

Value

  • If indices=TRUE, a list containing two vectors rr and cc giving row and column positions (in the image matrix). If indices=FALSE, a list containing vectors x and y giving actual coordinates of the pixels.

See Also

owin.object, as.mask

Aliases
  • nearest.raster.point
Examples
w <- owin(c(0,1), c(0,1), mask=matrix(TRUE, 100,100))  # 100 x 100 grid
  nearest.raster.point(0.5, 0.3, w)
  nearest.raster.point(0.5, 0.3, w, indices=FALSE)
Documentation reproduced from package spatstat, version 1.42-2, License: GPL (>= 2)

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