nearest.raster.point: Find Pixel Nearest to a Given Point

Description

Given cartesian coordinates, find the nearest pixel.

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

A window (an object of class "owin")
of type "mask" representing a binary pixel image.

indices

Logical flag indicating whether to return the
row and column indices, or the actual $x,y$ coordinates.

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.

Details

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

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.