CODEWITHSUNDEEP
r
J.M.Dundee
J.M.Dundee

Reputation: 11

Measuring distances between coordinates in 3d with R?

I have a dataframe not dissilmilar to this:

X   Y   Z    Point
1   1   1    1
2   1   1    2
1   2   1    3
1   1   10   4

I am trying to determine the distances between these different points and have calculated the Euclidean distances between each using the stats::dist() function. The distances calculated are as follows:

#Calculating distances
df <- dist(data, method = "euclidean")
#Output
df
         1        2        3
2 1.414214                  
3 2.236068 1.732051         
4 9.486833 9.273618 9.110434

However, comparing points 1 to either 2 or 3 should give distances of 1, and comparing 1 to 4 should give a distance of 9. I am unsure whether there is some form of normalisation or one axis is weighted more than another? I would appreciate help in finding the distances of these coordinates so I can scale it up to a much larger dataset!

Upvotes: 1

Views: 553

Answers (1)

GKi
GKi

Reputation: 39707

You are also including the column Point when calculating the distance. Subset to the coordinates in data e.g. with data[,1:3] or data[,-4].

dist(data[,1:3], method = "euclidean")
#         1        2        3
#2 1.000000                  
#3 1.000000 1.414214         
#4 9.000000 9.055385 9.055385

Upvotes: 2

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