Marker Chart (also known as a point chart) is like a line chart without the lines with markers enabled. A marker chart shows only endpoints of segments that make each line up.
This Chart represents training data for 10 best sportsmen. Their pulse values are distributed along the x-axis in the range [125,200] with the interval of 25 between major ticks. Three vertical ranges mean the pulse levels for an abstract person who does some sports. The lower one, 125 – 140, is a fat-burning zone; the second range, 140-155 is aerobic zone; the third range from 155 to 175 is an anaerobic zone and the last range stands for the maximum workout power zone, which is not recommended to gain unless you’re a professional preparing for the competitions.
The power values are distributed along the y-axis in the range [40, 160] with an interval of 40 between major ticks.
This Chart shows how many workouts these sportsmen had (the number of points), of which type and power. You can manage the chart performance by hovering or clicking the items of the legend, which is placed to the right from the chart: It will highlight the series or switch in off/on; you can turn all series off except for one to make its data clear to analyze.