Erik’s Brain

The reward of a thing well done...

Proportional Spacing on a Graph's Axis

Bear with me. I haven’t done much with graphing since physics class my senior year of high school. East Bay Crushers RULE!

Time X Axis

If you were to graph the price of something over time, it would make sense to have the date or time along the x-axis and the price on the y-axis. Let’s also say that you got price info at inconsistent intervals. So you have the price for November 17th, 23rd, 30th and then December 1st and 10th. It would make sense to have the plot points for November 30th and December 1st closer to each other than the plot points for November 17th and 23rd, right? One day is much less than six days and that can easily be expressed visually. Also, the horizontal spacing between December 1st and 10th should be greater than any of the others.

Why is this so hard to do?

Granted, I’m using Numbers, which probably isn’t nearly as powerful as Excel. But, based on a quick Google search or two, it seems like Excel isn’t much better at this.

It seems like this would be a common use case. Am I crazy? Am I just going about this the wrong way?

Update: Saturday, June 9, 2012

This post from early 2010 shed some light on the issue for me. The key is to use a scatter chart, then turn on connection lines between the data points. That gets me close enough to what I wanted.

The only type of chart that is a true X-Y plot is the scatter chart. It is the chart icon that looks like a shotgun blast. Your dates and the values must both be in data column, neither can be in a header column. After creating the chart, you will most likely have to go to the Metrics Inspector and rotate the X-axis labels (dates are usually too long to display horizontally). The chart plots data points. You can connect the points with lines in the Table Inspector.