I need to display some data for users to look at at track their progress, and at first I thought of using a line chart, which at a glance seems okay.
But the problem is there are 2 different units displayed, kgs and cm. (Technically there are 4, kgs/lbs, and cm/inches but the user chooses which metric they want on a settings page).
The issue I think the chart has, is the value could be mis-read. You see the value is 50, but because I can't label the V axis, and there are multiple units, you have to look further to understand what the value applies to.
Is this as much of a problem as I think it is, or am I thinking too hard about this?
If this could be an issue, does anybody have any suggestions on how else I could display this data?
Here's a JSFiddle with some test data, and a chart if anybody wants to have a play with it.
Update: This is what I ended up with.