chordDiagram() with overlapping ends in R

Question

I am trying to produce a modified version of a Chord Diagram in R using the chordDiagram() function in the circlize package in R.

Suppose we have this toy example (as for the documentation of the package):

require(circlize)
df = expand.grid(letters[1:3], LETTERS[1:4])
df$value = 1
df$value2 = 3 
chordDiagram(df[, 1:3])

The output will be pretty straightforward:

Now, the problem is: let's suppose that I need to make two "ends" overlap to represent an intersection, for example, the ribbon going from b-->A and the ribbon going from a-->A, so that they end in the same sector "merging" each other (such as in the figure below).

Is that possible? I didn't find any example in the documentation nor I was able to perform this task by tweaking the options.

Hope that I made myself clear. Thank you for any try.

score 1 · Answer 1 · answered Mar 24 '22 at 18:32

If I understand you correctly, you want to make overlapping parts in the diagram. So for example S3 -> E2 and S2 -> E2. You create a matrix which has a format so that you get overlapping paths in the diagram. I will give you an example with the following code:

First create a matrix with connection between S and E with different values:

library(circlize)
set.seed(999)
mat = matrix(sample(18, 18), 3, 6) 
rownames(mat) = paste0("S", 1:3)
colnames(mat) = paste0("E", 1:6)
mat

   E1 E2 E3 E4 E5 E6
S1  4 14 13 17  5  2
S2  7  1  6  8 12 15
S3  9 10  3 16 11 18

Next create a dataframe which has a format of columns with character from to another character with values to check what the patterns are more easily:

df = data.frame(from = rep(rownames(mat), times = ncol(mat)),
                to = rep(colnames(mat), each = nrow(mat)),
                value = as.vector(mat),
                stringsAsFactors = FALSE)

   from to value
1    S1 E1     4
2    S2 E1     7
3    S3 E1     9
4    S1 E2    14
5    S2 E2     1
6    S3 E2    10
7    S1 E3    13
8    S2 E3     6
9    S3 E3     3
10   S1 E4    17
11   S2 E4     8
12   S3 E4    16
13   S1 E5     5
14   S2 E5    12
15   S3 E5    11
16   S1 E6     2
17   S2 E6    15
18   S3 E6    18

Plot the output using mat:

chordDiagram(mat)

As you can see, there is some overlap in the paths of S3 -> E2 and S2 -> E2.

Thank you for your effort, but unfortunately this is not what I had in mind. The overlap should not be (only) on the "paths" (or ribbon, whatever you call it), but also on the section in which the two ribbons end. You can see an example of what I meant in the second figure, with the overlap of the ends of the two ribbons going from b->A and to a->A — userq8957289475, Mar 25 '22 at 15:40

chordDiagram() with overlapping ends in R

1 Answers1