[R] distance between consecutive points

Darcy Webber darcy.webber at gmail.com
Wed Feb 16 01:09:59 CET 2011


Dear R users,

I have two coloumns of data, say x and y, referring to a list of
points in 2D space. I am trying to develop a code that will give me
the distances (using Pythagoras) between consecutive points (xi,yi)
and (xi+1,yi+1). So far I have come up with the following:

for (i in 1:length(x)) d<-sqrt((x[i+1]-x[i])^2+(y[i+1]-y[i])^2)

For example, if I use the two points (note, I have hundreds of points for x,y)
x<-c(64.59,64.60)
y<-c(-179.28,-179.28)

d should be 0.01.

But it just doesn't give me the correct answer and I can't figure out
why. Any help would be much appreciated.

Cheers,
D'Arcy



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