I am working on a report that requires a multi-line chart (representing how a given value varies over time among different groups) They are displayed in a single chart sharing both axis. My problem is that at some stages, the data looks similar to this:

    DAY:  1   2   3   4
GROUP A: 10  12  15  18
GROUP B: 11  12  15  20

Now, the lines joining days 2 and 3 will overlap with each other, so the one that is drawn later erases the previous line. I've thought of a few solutions, not all of them entirely convincing:

  • Color mixing: let's say I draw the series for group A in red and the one for group B in yellow. I would draw the overlapping section in orange.
  • Randomization: adding a small random value to each point, big enough to make the lines distinct, but small enough to keep the "fake data" as close to the original as possible.
  • Layers: making the first line slightly thicker, so that when the second line is drawn on top, it doesn't completely disappear.

In my real problem, I sometimes have 3 or even 4 overlapping lines at some sections, and each line has about 20 points. I would like to know if there are other more interesting solutions (or at least, which of the ones I thought of you would recommend as a "best practice")

This is an example of one of those charts (in its pure form, without any correction) enter image description here

Here the "randomized" chart: enter image description here

  • 1
    Do your line segments between the corners have some information value or are they only for following the series? If they are not intended to be red between the actual data points, you could use discrete chart types which are intended for 2 variables and one value.
    – user82991
    Commented Aug 8, 2019 at 9:01
  • @user287001 The line segments contain no information.
    – David
    Commented Aug 15, 2019 at 9:31
  • If you are using those light colors use a black background.
    – Rafael
    Commented May 11, 2020 at 14:12

2 Answers 2


This happens alot with charts and honestly there's nothing wrong with overlapping values, people will get it when some values are identical. However, some ideas to fix this:

  • use a bar chart (if possible with your data)
  • use filled shapes instead of just simple lines (if possible with your data)
  • use multiply on the top line, so when overlapping, it automatically changes color

enter image description here

  • What do you mean with "use multiply"?
    – David
    Commented Aug 7, 2019 at 14:51
  • Blending mode Multiply. Its available in Photoshop, Illustrator.. what software are you using?
    – Lucian
    Commented Aug 7, 2019 at 14:53
  • I am making these charts with R. I thought this solution worked fine, but when there are more than 2 lines it can get confusing
    – David
    Commented Aug 7, 2019 at 14:55

Just made some tests. 3D looking graphs are difficult to read when there are many days and groups. I recommend you to use conventional spreadsheet style graphs. Here's an example in LibreOffice Calc (=freeware):

enter image description here

Creating these needs only few clicks. There's a column graph and a line chart with dots. Both of them present the same data.

The graphs can be exported as vector for ex. by copying and pasting them to Illustrator or other drawing program. Here one chart is pasted to Inkscape and the coordinate lines are colored and made thicker:

enter image description here

The numbers are still text objects. The graph lines are unfortunately colored rectangles, so they should get the final thickness in the spreadsheet.

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