# distanceFromPoints: Distance from points In raster: Geographic Data Analysis and Modeling

## 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

 `1` ```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)

RasterLayer

## References

C.F.F. Karney, 2013. Algorithms for geodesics, J. Geodesy 87: 43-55. https://dx.doi.org/10.1007/s00190-012-0578-z.

`crs`, `distance`, `gridDistance`, `pointDistance`

## Examples

 ```1 2 3 4 5 6 7 8``` ```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) ```

### Example output

```Loading required package: sp
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
NOTE: rgdal::checkCRSArgs: no proj_defs.dat in PROJ.4 shared files
```

raster documentation built on Nov. 17, 2017, 5:51 a.m.