How Excel Charts Work A chart has an x-axis range and a y-axis range to show the correlation between two different data sets. The x-axis is the horizontal category line.

Edit your horizontal chart data in Excel 2007 with a variety of available tools. Change the data, format, titles and scale of your scatterplot's horizontal axis.

If you have uneven distribution of data in your Excel chart, here is a better way to change the automatic axis settings.