By David Crowther
Question:
How does the Time Manager Tool work within QGIS?
Answer:
The Time Manager tool, available as a plugin for QGIS, allows you to use a TIME Slider to filter your datasets, showing changes through time. You can either use time or date settings to filter your input layer and create an animation to show changes in your data over that time/date period.
In this demo example, we will use a Polygon Layer of Planning Applications, however the Time Slider tool can also be used to filter Point, Line and Raster datasets.
These Planning Applications have a thematic style assigned based on the Progress of each Planning Application.
They also have a Created field, which stores the Day (date) of when the Planning Application was created. We can see that the first record was created on 01st July 2021 (2021-07-01) and then we have records being created on the 2nd, 3rd, 4th etc…
Using the Time Manager tool, we will run an animation that will enable us to identify which Planning Applications were created on each day through that week. As the animation runs, it will simply apply a FILTER to the dataset to only show the records that meet that new DATE value.
The Time Manager tool can be installed from a ZIP file from this location – https://plugins.qgis.org/plugins/timemanager/
Once you have downloaded the ZIP file, in QGIS open the Plugin Manager and choose to install from a ZIP file. Choose the location of the ZIP file and then choose Install Plugin.
The plugin will be unzipped and installed into your QGIS, with it opening into a new panel at the bottom of the map window.
To setup the Time Manager tool choose the Settings button.
Firstly, choose Add Layer to choose the layer you wish to apply within the Time Manager tool.
In the select a layer config window choose:
- the Layer to be the Planning Applications layer.
- the Start time to be the field containing the DATE or TIME to filter against – here we will choose the Created field.
- the End time to be the same as the start.
In the Animation options, set the Show Frame for 4000 milliseconds (4 seconds) and also choose to loop the animation.
Finally set the Time Frame Size to be 1 – DAYs. This controls how the time slider skips to the next timeframe – hour, day, week, year etc….
To activate the Time Slider, choose the ON button.
As soon as you press the On button this will apply a FILTER to the layer using the current TIME/DATE setting – 2021-07-01 – as such the map will update to only show the features where the Created Date = 2021-07-01.
If you Browse the Attribute table for the Layer you can see that the FILTER has also been applied to the records here.
To play through the Animation choose the PLAY button in the Time Manager tool.
As the Time Manager progresses to the next DAY – 2021-07-02 – the Planning Applications are re-filtered to only show the records Created on that new date.
The Time Manager tool then pauses for the selected transition time (4000 milliseconds) before then progressing to the next DAY – 2021-07-03 – and re-filtering the Planning Application again.
If you leave the animation running you then get a view of how the dataset changes from the start (2021-07-01) to end date 2021-07-10, and it will loop through and start the animation again.
Using the Export Video button, the frames can then be exported to help you create an animation of the timeline.
After exporting you will have image files for each DAY in the Timeline.
You can use a GIF animator tool to create an animated gif that will auto run through the Timeline and loop for playback!