Independent Series

By using the connectSeparated attribute, it's possible to display a chart of several time series with completely independent x-values.

The trick is to specify values for the series at the union of the x-values of all series. For one series' x values, specify null for each of the other series.

For example, say you had two series:

x	A
2	2
4	6
6	4

x	B
1	3
3	7
5	5

Then you would specify the following CSV or native data:

(CSV)

X,A,B
1,,3
2,2,
3,,7
4,6,
5,,5
6,4,

(native)

[
[1, null, 3],
[2, 2, null],
[3, null, 7],
[4, 6, null],
[5, null, 5],
[6, 4, null] ]

Encoding a gap

There's one extra wrinkle. What if one of the series has a missing value, i.e. what if your series are something like

x	A
2	2
4	4
6	(gap)
8	8
10	10

x	B
1	3
3	5
5	7

The gap would normally be encoded as a null, or missing value. But when you use connectSeparatedPoints, that has a special meaning. Instead, you have to use NaN. This is a bit of a hack, but it gets the job done.

(CSV)

x,A,B
1,,3
2,2,
3,,5
4,4,
5,,7
6,NaN,
8,8,
10,10,

(native)

[ [1, null, 3],
  [2, 2, null],
  [3, null, 5],
  [4, 4, null],
  [5, null, 7],
  [6, NaN, null],
  [8, 8, null],
  [10, 10, null] ]