distanceFromPoints: Distance from points

In raster: Geographic Data Analysis and Modeling

Distance from points

Description

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).

Usage

distanceFromPoints(object, xy, filename='', ...) 

Arguments

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 writeRaster

Details

Distances for longlat data are computed on the WGS84 spheroid using GeographicLib (Karney, 2013)

Value

RasterLayer

References

C.F.F. Karney, 2013. Algorithms for geodesics, J. Geodesy 87: 43-55. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/s00190-012-0578-z")}.

See Also

crs, distance, gridDistance, pointDistance

Examples

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)

raster documentation built on Oct. 3, 2024, 1:08 a.m.