Using a timeline, you can visualize your data along a temporal axis. Timelines complement the spatial view of your data on the map by showing where in time your data falls. By plotting your data along a timeline, you can understand the temporal order of your data and discern temporal trends that emerge. When combined with time enabling your map and using the time slider, a timeline gives a complete view of your temporal data and can enhance contextual understanding.
Data can be plotted on a timeline if time has been enabled on the layer on the Layer Properties dialog box. This data can have either a single time stamp, in which case it appears as points along the timeline, or a start and an end time, in which case it appears as a linear time span. Data that does not have a location assigned to it can also be plotted along a timeline. A timeline can contain multiple layers from the same map and unique values within a layer, allowing you to view multiple aspects of your data along the same temporal axis. These layers can be viewed in the same horizontal lane, or in distinct lanes, giving you a matrix by which you can compare features through both time and their category or lane.