Single Line Graphs — Definition

Definition

A single line graph follows one measured quantity across an ordered set of observations. Each plotted point pairs a horizontal value, such as time, with a vertical value, such as tank volume or distance.

Joining the points makes increases, decreases and unchanged intervals easier to see. The graph contains one series, so the first task is to read its coordinates accurately rather than compare a legend of groups.

A downward segment means the displayed quantity fell; its physical meaning depends on the axis label. Water level, cumulative distance and speed cannot be interpreted by the same shortcut.