Area Chart looks like a Line Chart with the space between the line itself and the X-Axis filled with color. Area Charts are good at demonstrating how an amount of something changes continuously. A Step-Area means that the points of this Area Chart by default are the centers of small horiziontal lines, forming a kind of a diagram which reminds of signal monitoring. Any Range Chart point has two values: min and max, so it shows a range of values corresponds to the same category - for example, the minimum and the maximum temperature values that were registrated in a month.
This Chart has an only series describing connection timeouts during each hour of a day. There are no negative values for obvious reasons; the Y-Axis range is from 0 to 1200 ms, and the categories placed on the X-Axis demonstrate the day hours. The legend is disabled. Tooltips give all the information about the points: the highest, the lowest values and the current hour.