# Stripchart with 3 different units

The requirement is:

Stripchart: A virtual, moving paper display with three data channels superimposed. Different colour and or linetype will indicate each data type (temperature, wind speed, insolation).

How can we represent different units in just one stripchart?

Got any ideas?

Most simply, you can include the units in parenthesis after each label in the legend. The difference in colors definitely helps pick apart the different data, keep that in there.

The axis labels is where this question gets a bit more challenging. One option is to have units on both sides of the graph. In this example, two distinct ideas are being conveyed in one graph. It places the "units sold" title and units on the left, and total transactions on the right. This provides two separate units, both on the vertical axis. Again, color would help differentiate them here, so the user knows which side to look at the for units.

However, you are hoping to convey three distinct units on one graph, so a more creative solution is required. One might be multiple axes as in this question. Another option you might consider is displaying numeric values next to points on the graph. This can easily make the graph cluttered or unreadable if implemented without care.

Another interesting option is using a single scale. Let's say I want to express a series of length measurements with a minimum of 1 meter and a maximum of 100 meters. Also, a weight between 10 grams and 10 kilograms. Finally, a time between 0.1 seconds and 0.5 seconds. In summary:

``````Measurement  Minimum   Maximum
Length       1 meter   100 meters
Weight       10 grams  10 kilograms
Time         0.1 sec   0.5 seconds
``````

We label the axis from 1 to 100, with set increments between. Then we might say the units for length are meters, weight as decagrams (increments of 10 grams) and time in deciseconds (tenths of a second). While these units might need extra emphasis to be clear, you can use a single string of numbers on the axis.

Consider why you are trying to overlay three series of data on one graph. If you want to easily compare their values, make sure the scale is appropriate to convey this comparison.

• When comparing values with radically different units often the important part is being able to visually digest the relationship between them to make statements such as "As insolation trends up, Wind speed follows." As long as that's the case, the single scale path is probably the best. – NotMe Aug 24 '16 at 22:50

It sounds like you want to display three different data sets (wind speed, temperature, isolation) in a single chart. I assume the data would all share the same x-axis values (e.g., time-series data?) But each data set would require its own y-axis?

Try interacting with this demo: http://demos.zingchart.com/view/JE410YXV

Each data set is charted to its own y-axis scale. For illustration purposes, you can see three scales on the left-hand side. However, you do have the option of blending the scales together to display a single axis line. This would allow you to display three different data sets in a single chart.

Read this X/Y-Axis Scales Tutorial for more information on the different scale elements and how you can customize them. You can also add a legend, tooltips (not shown in the above demo), and/or crosshairs to explain what each data set represents.

Disclosure: I'm a member of the ZingChart team. Let me know if you have further questions.