Re: [R-sig-eco] How to calculate geographical coordinates of sampling points following (by bearing and distance) a georeferenced one?
On Fri, Apr 6, 2012 at 10:26 PM, Tammy Wilson 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.
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Re: [R-sig-eco] How to calculate geographical coordinates of sampling points following (by bearing and distance) a georeferenced one?
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
On Wed, Apr 4, 2012 at 11:02 PM, Ivailo wrote:
> Der fellow R-users,
>
> I have several sampling sites and in each site the "starting" plot
> (i.e. the first one that have been sampled) is georeferenced with a
> GPS but the following ones are just described by their distance and
> bearing in relation to the previous one.
>
> Is there a quick way to calculate (by using some of the spatial
> R-packages) the geographic coordinates of the sapling plots at each
> location that have not been explicitly georeferenced?
>
> Cheers,
> Ivailo
> --
> UBUNTU: a person is a person through other persons.
>
> ___
> R-sig-ecology mailing list
> R-sig-ecology@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
--
Tammy L. Wilson
Ecologist
(\(\
(>`.’)<
(,,)(‘’)(‘’)
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Re: [R-sig-eco] How to calculate geographical coordinates of sampling points following (by bearing and distance) a georeferenced one?
I cannot remember the names, but there would be support for this in the maptools or geosphere package I am sure On Thursday, April 5, 2012, Ivailo wrote: > Der fellow R-users, > > I have several sampling sites and in each site the "starting" plot > (i.e. the first one that have been sampled) is georeferenced with a > GPS but the following ones are just described by their distance and > bearing in relation to the previous one. > > Is there a quick way to calculate (by using some of the spatial > R-packages) the geographic coordinates of the sapling plots at each > location that have not been explicitly georeferenced? > > Cheers, > Ivailo > -- > UBUNTU: a person is a person through other persons. > > ___ > R-sig-ecology mailing list > R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology > -- Michael Sumner Institute for Marine and Antarctic Studies, University of Tasmania Hobart, Australia e-mail: mdsum...@gmail.com [[alternative HTML version deleted]] ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
[R-sig-eco] How to calculate geographical coordinates of sampling points following (by bearing and distance) a georeferenced one?
Der fellow R-users, I have several sampling sites and in each site the "starting" plot (i.e. the first one that have been sampled) is georeferenced with a GPS but the following ones are just described by their distance and bearing in relation to the previous one. Is there a quick way to calculate (by using some of the spatial R-packages) the geographic coordinates of the sapling plots at each location that have not been explicitly georeferenced? Cheers, Ivailo -- UBUNTU: a person is a person through other persons. ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
