使用线连接所有点，并使用R在其上方书写文本

Question

I'm trying to connect every point in my array with all other points in this array using line segment and write some text slightly above this lines . So, I want to achieve next:

I already tried to use segments() and lines() functions, but I don't know how can I do exactly what I described.

And as I said, now I have only array of coordinates and array of strings which I want to write. How can I achieve this(It will be good if I will need to use only standard R libraries)?

UPD:

dataset.csv:

,A,B,C
A,0,1,2
B,1,0,3
C,2,3,0

script.r:

myDataset <- read.csv("dataset.csv")
row.names(myDataset) <- myDataset[, 1]
myDataset <- myDataset[, -1]
d <- dist(myDataset)
fit <- cmdscale(d,eig=TRUE, k=2)
x <- fit$points[,1]
y <- fit$points[,2]

Answer 1

Here's an example that uses combn to generate combinations of two points and then draw lines between them and to compute distances and write them in the middle too.

#DATA
set.seed(42)
df = data.frame(x = rnorm(4),  y = rnorm(4))

#DRAW POINTS    
plot(df)

#DRAW LINES
combn(1:NROW(df), 2, function(x)
    lines(df[x,]), simplify = FALSE)

#WRITE TEXT
combn(1:NROW(df), 2, function(x)
    text(x = mean(df[x,1]),  #calculate center point x-value in the line
        y = mean(df[x,2]),  #calculate center point y-value in the line
        labels = round(dist(df[x,]), 2), #calculate distance to write
        srt = 180 * atan(diff(df[x, 2])/diff(df[x,1]))/pi, #calculate rotation angle of text
        pos = 3, #place text slightly above given x and y
        font = 2), #bold text
    simplify = FALSE)

UPDATE

myDataset <- read.csv(strip.white = TRUE, stringsAsFactors = FALSE, header = TRUE, text = ",A,B,C
A,0,1,2
                      B,1,0,3
                      C,2,3,0")
row.names(myDataset) <- myDataset[, 1]
myDataset <- myDataset[, -1]
d <- dist(myDataset)
fit <- cmdscale(d,eig=TRUE, k=2)
x <- fit$points[,1]
y <- fit$points[,2]

df = data.frame(x, y)

#DRAW POINTS
plot(df, asp = 1)
text(x = df[,1], y = df[,2], labels = rownames(df), pos = 1)

#Create a list of combination of indices
temp = combn(1:NROW(df), 2, simplify = FALSE)

#DRAW LINES
sapply(temp, function(i) lines(df[i,]))

#WRITE TEXT
sapply(temp, function(x)
    text(x = mean(df[x,1]),  #calculate center point x-value in the line
        y = mean(df[x,2]),  #calculate center point y-value in the line
        labels = myDataset[cbind(which(row.names(myDataset) == row.names(df)[x[1]]),
                    which(colnames(myDataset) == row.names(df)[x[2]]))],
        srt = 180 * atan(diff(df[x, 2])/diff(df[x,1]))/pi, #calculate rotation angle of text
        pos = 3, #place text slightly above given x and y
        font = 2), #bold text
    simplify = FALSE)

Answer 2

Trying to achieve this with graphics primitives (such as lines ) is bound to be a pain.

Use a dedicated library for graph plotting instead, eg ggraph . The “Edges” vignette has an example with edge labels:

ggraph(simple, layout = 'graphopt') + 
    geom_edge_link(aes(label = type), 
                   angle_calc = 'along',
                   label_dodge = unit(2.5, 'mm'),
                   arrow = arrow(length = unit(4, 'mm')), 
                   end_cap = circle(3, 'mm')) + 
    geom_node_point(size = 5)

The one drawback: ggraph doesn't allow you to explicitly set the node positions; however, you can manipulate them manually.