Area Charts are similar to the Line Charts: they are intended to represent the data that can be arranged in a table on a worksheet, they use standard two-dimensional coordinate system and both are mostly used to show continuous changes. By having an area between the zero line and the series line colored, Area Charts emphasize the magnitude of change over a period of time and draw attention to a total value across a trend.
This Area chart has only one series, which shows the number of unique site visitors during a year. Categories on the X axis are months; Y axis holds the values. One important thing about the vertical scale: the values spread along the vertical axis look special, that’s because the Y scale type is changed from the default (ordinal) to logarithmic. Logarithmic scale helps when there is a large range of values in the data, it reduces the difference and makes the chart easier to read.
All data points are marked and all area labels are enabled, so you can see each point’s value even without hovering any of them. But tooltips are enabled as well; when you hover anywhere above a category, the tooltip of the point that belongs to this category is shown. Tooltips show the category and the number of visits, this is a default tooltips formatting: series name and point value, formatting can be changed in a number of ways.