Timeline

6.10 Timeline

The IDV makes use of a timeline widget in a variety of areas. The timeline allows you to see the temporal distribution of a set of times and easily select them. There can also be a date selection mechanism (see below) that allows you to select based on a range, interval, etc.

Image 1: Chooser Timeline

The View Managers use the timeline to show the animation time set and the times of the different displays. Here, the timeline is used for informational purposes and is not used to select times. This can be shown through the menu. The gray timeline represents non-visible displays. Double clicking in a timeline sets the animation step to that time.

Image 2: Animation Times

Timeline Navigation

The timeline supports a variety of navigation mechanisms:

Event	Action
Left Mouse Drag	Change visible range or date selection range.
Left/Right Arrow	Change visible range. Use Control-Key to change date selection. Use Shift-Key to use larger increment.
Up/Down Arrow	Zoom in/out visible range. Use Control-Key to change date selection. Use Shift-Key to use larger increment.
Mouse Click; Control-Click; Shift-Click	Select individual times, multiple times or a range of times
Shift-Drag	When not showing the date selection mechanism you can choose a range of times with shift-drag
Right Mouse Click	This brings up a popup menu that allows you to show the properties dialog, go to particular current date ranges, set the interval, range, skip factor and count of the date selection.

Date Selection

The date selection is defined by:

Start/End date: These define the range to look within.
Interval: If defined, this allows you to select dates every N time units. For example, you can set the interval to be one hour. The times that are selected are the ones closest to the one hour interval ticks.
Before/After Range: These are displayed by the little gray triangles in the timeline. By default, the ranges that we use are one half the size of the interval. However, you can set the range both before and after the interval tick. So for example, if you want to just consider times within 15 minutes before the interval but nothing after the interval set the Before Range to be 15 minutes and the After Range to be 0 minutes.
Count: You can specify a max number of times that will be selected. Only the most recent N times will be selected.
Skip Factor: This says to skip every N'th time that would be selected. For example, the date selection first considers the interval/ranges (if defined), then it applies the skip (e.g., only every 3rd time), then it looks at the max count.

These can be accessed by right-clicking in the timeline to show a popup menu. The menu allows you explicitly define these settings through a Properties dialog or (much more easy) set them directly with sub-menu choices.

Unidata's Integrated Data Viewer > Tools