Distance from points
The function calculates the distance from a set of points to all cells of a Raster* object.
The distance unit is in meters if the coordinate reference system (crs) of the Raster* object is (+proj=longlat) or assumed to be if the crs is NA. In all other cases it is in the units defined by the crs (which typically is meters).
distanceFromPoints(object, xy, filename='', ...)
object |
Raster object |
xy |
matrix of x and y coordinates, or a SpatialPoints* object. |
filename |
character. Optional filename for the output RasterLayer |
... |
Additional arguments as for |
Distances for longlat data are computed on the WGS84 spheroid using GeographicLib (Karney, 2013)
RasterLayer
C.F.F. Karney, 2013. Algorithms for geodesics, J. Geodesy 87: 43-55. doi: 10.1007/s00190-012-0578-z.
r <- raster(ncol=36,nrow=18) xy <- c(0,0) d1 <- distanceFromPoints(r, xy) crs(r) = '+proj=utm +zone=12 +datum=WGS84' d2 <- distanceFromPoints(r, xy) par(mfrow=c(1,2)) plot(d1) plot(d2)
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