Analyzing spatio-temporal data using a GIS can be a tedious task without the correct tools. A series of techniques has been developed to visualize spatio-temporal data. These techniques can be divided into two classes: static visualizations and dynamic animations.
In static maps, temporal change can be visualized using appropriate different symbology or annotations. Another option is to create map series with one map for every time frame of interest.
Animated maps are best known from TV weather forecast shows. Animations enable the map user to recognize spatio-temporal relationships more intuitively than static maps could.
Interactive animated maps can help the user to explore and analyze spatio-temporal data. The literature lists the following minimum functionality for interactive animated maps: stop, play, step forward and looping functions. The efficiency of animations can be increased by allowing the user to control the size of visualized time frames and the speed of the animation.
All these functions (and more) have been implemented into Time Manager for QGIS. The user has full control over the animation. Animations can be played forward or backward at any speed. The user can also navigate through the animation step by step or jump to desired points in time using the slider or time input field.
Besides viewing animations inside QGIS, animations can also also be exported frame-by-frame. These single images can be used as they are or combined into a video file using tools like mencoder.
The connection between spatial objects and the temporal dimension is established using timestamps. A timestamp can consist of either a point in time (e.g. the GPS position of a tracked object at one moment) or a timespan (e.g. a plot of land has been used to grow corn from 2002 to 2005).
Time Manager can handle multiple temporal layers at a time. It’s also possible to specify an offset between layers to achieve different effects. Any vector layer (point, line or polygon) with a correctly formated timestamp attribute can be used. All Time Manager settings are saved into the QGIS project file and are restored when loading an existing project.
According to FOSSGIS presentation feedback the following features are on the most wanted list: support for raster layers and support for year-only timestamps before 19xx.
The plugin installation includes a user manual for quick reference.
Update: For up to date info check Time Manager project page.