Return the (approximate) middle pixel on a raster
middlePixel(ras)
A Raster
or SpatRaster
object
This calculation is slightly different depending on whether
the nrow(ras)
and ncol(ras)
are even or odd.
It will return the exact middle pixel if these are odd, and
the pixel just left and/or above the middle pixel if either
dimension is even, respectively.