[R-sig-eco] How to calculate geographical coordinates of sampling points following (by bearing and distance) a georeferenced one?

[Ivailo]

On Fri, Apr 6, 2012 at 10:26 PM, Tammy Wilson <t.w at aggiemail.usu.edu> wrote:
> Trigonometry will work for projected coordinate systems like UTM:
>
> Try this:
> # number of points
> n = 30
>
> # reference location
> ref.pt = cbind(1,2)
>
> # generate some random directions
> # This can be your list of your bearings converted to radians
> dir <- runif(n,0,2*pi )
>
> # generate some random distances
> # This can be your list of distances in map units (e.g. m)
> dist <- runif(n,0.5,10)
>
> #empty matrix for coordinates
> coords.mat = cbind(rep(0,n),rep(0,n))
>
> #using trigonometry to calculate object location
> for (i in 1:n){
>              coords.mat[i,1] = ref.pt[1]+(sin(dir[i])*dist[i])
>              coords.mat[i,2] = ref.pt[2]+(cos(dir[i])*dist[i])
>        }
> plot (coords.mat)
> points(ref.pt,col=2)
>
> Best,
> Tammy

Thank you for the code, Tammy! Meanwhile Michael Summer pointed my
attention the the geosphere package and the destPoint() function seems
to do exactly what I was
searching for.

Cheers,
Ivailo
-- 
UBUNTU: a person is a person through other persons.