Tag Archives: Time Manager

This is a guest post by Karolina Alexiou (aka carolinux), Anita’s collaborator on the Time Manager plugin.

As of version 2.1.5, TimeManager provides some support for stepping through WMS-T layers, a format about which Anita has written  in the past.  From the official definition, the OpenGIS® Web Map Service Interface Standard (WMS) provides a simple HTTP interface for requesting geo-registered map images from one or more distributed geospatial databases. A WMS request defines the geographic layer(s) and area of interest to be processed. The response to the request is one or more geo-registered map images (returned as JPEG, PNG, etc) that can be displayed in a browser application. QGIS can display those images as a raster layer. The WMS-T standard allows the user of the service to set a time boundary in addition to a geographical boundary with their HTTP request.

We are going to add the following url as the web map provider service:

From QGIS, go to Layer>Add Layer>Add WMS/WMST Layer and add a new server and connect to it. For the service we have chosen, we only need to specify a name and the url.

Select the top level layer, in our case named nexrad_base_reflect and click Add. Now you have added the layer to your QGIS project.

To add it to TimeManager as well, add it as a raster with the settings from the screenshot below. Start time and end time have the values 2005-08-29:03:10:00Z and 2005-08-30:03:10:00Z respectively, which is a period which overlaps with hurricane Katrina. Now, the WMS-T standard uses a handful of different time formats, and at this time, the plugin requires you to know this format and input the start and end values in this format. If there’s interest to sponsor this feature, in the future we may get the format directly from the web service description. The web service description is an XML document (see here for an example) which, among other information, contains a section that defines the format, default time and granularity of the time dimension.


If we set the time step to 2 hours and click play, we will see that TimeManager renders each interval by querying the web map service for it, as you can see in this short video.

Querying the web service and waiting for the response takes some time. So, the plugin requires some patience for looking at this particular layer format in interactive mode. If we export the frames, however, we can get a nice result. This is an animation showing hurricane Katrina progressing over a 30 minute interval.


If you want to sponsor further development of the Time Manager plugin, you can arrange a session with me – Karolina Alexiou – via Codementor.

Today was the final day of #QGIS2015 the first joint QGIS conference and developer meeting. I had the pleasure to meet Time Manager co-developer Karolina Alexiou aka carolinux in person and give a talk including a hands-on workshop on Time Manager together. Time Manager makes it possible to explore spatio-temporal data by creating animations directly in QGIS.

The talk presents QGIS visualization tools with a focus on efficient use of layer styling to both explore and present spatial data. Examples include the recently added heatmap style as well as sophisticated rule-based and data-defined styles. The focus of this presentation is exploring and presenting spatio-temporal data using the Time Manager plugin. A special treat are time-dependent styles using expression-based styling which access the current Time Manager timestamp.

To download the example data and QGIS projects download

Today’s post is a short tutorial for creating trajectory animations with a fadeout effect using QGIS Time Manager. This is the result we are aiming for:

The animation shows the current movement in pink which fades out and leaves behind green traces of the trajectories.

About the data

GeoLife GPS Trajectories were collected within the (Microsoft Research Asia) Geolife project by 182 users in a period of over three years (from April 2007 to August 2012). [1,2,3] The GeoLife GPS Trajectories download contains many text files organized in multiple directories. The data files are basically CSVs with 6 lines of header information. They contain the following fields:

Field 1: Latitude in decimal degrees.
Field 2: Longitude in decimal degrees.
Field 3: All set to 0 for this dataset.
Field 4: Altitude in feet (-777 if not valid).
Field 5: Date – number of days (with fractional part) that have passed since 12/30/1899.
Field 6: Date as a string.
Field 7: Time as a string.

Data prep: PostGIS

Since any kind of GIS operation on text files will be quite inefficient, I decided to load the data into a PostGIS database. This table of millions of GPS points can then be sliced into appropriate chunks for exploration, for example, a day in Beijing:

    trajectories.t_datetime + interval '1 day' as t_to_datetime,
   FROM geolife.trajectories
   WHERE st_dwithin(trajectories.geom,
   AND trajectories.t_datetime >= '2008-11-11 00:00:00'
   AND trajectories.t_datetime < '2008-11-12 00:00:00'

Trajectory viz: a fadeout effect for point markers

The idea behind this visualization is to show both the current movement as well as the history of the trajectories. This can be achieved with a fadeout effect which leaves behind traces of past movement while the most recent positions are highlighted to stand out.

Map tiles by Stamen Design, under CC BY 3.0. Data by OpenStreetMap, under ODbL.

Map tiles by Stamen Design, under CC BY 3.0. Data by OpenStreetMap, under ODbL.

This effect can be created using a Single Symbol renderer with a marker symbol with two symbol layers: one layer serves as the highlights layer (pink) while the second layer represents the traces (green) which linger after the highlights disappear. Feature blending is used to achieve the desired effect for overlapping markers.

Screenshot 2015-05-06 23.52.40

The highlights layer has two expression-based properties: color and size. The color fades to white and the point size shrinks as the point ages. The age can be computed by comparing the point’s t_datetime timestamp to the Time Manager animation time $animation_datetime.

This expression creates the color fading effect:


(Note that before QGIS 2.10, we had to use $animation_datetime instead of animation_datetime().)

and this expression makes the point size shrink:

  minute(age(animation_datetime(),"t_datetime")), 0,60, 24,0, 0.2 ) 


I’m currently preparing this and a couple of other examples for my Time Manager workshop at the upcoming 1st QGIS conference in Nødebo. The workshop materials will be made available online afterwards.


[1] Yu Zheng, Lizhu Zhang, Xing Xie, Wei-Ying Ma. Mining interesting locations and travel sequences from GPS trajectories. In Proceedings of International conference on World Wild Web (WWW 2009), Madrid Spain. ACM Press: 791-800.
[2] Yu Zheng, Quannan Li, Yukun Chen, Xing Xie, Wei-Ying Ma. Understanding Mobility Based on GPS Data. In Proceedings of ACM conference on Ubiquitous Computing (UbiComp 2008), Seoul, Korea. ACM Press: 312-321.
[3] Yu Zheng, Xing Xie, Wei-Ying Ma, GeoLife: A Collaborative Social Networking Service among User, location and trajectory. Invited paper, in IEEE Data Engineering Bulletin. 33, 2, 2010, pp. 32-40.

Over the last couple of weeks, Karolina has been very busy improving and expanding Time Manager. This post is to announce the 1.6 release of Time Manager which brings you many fixes and exciting new features.

Screenshot 2015-03-25 17.58.38

What’s this feature interpolation you’re talking about?

Interpolation is really helpful if you have multiple observations of the same (moving) real-world object at different points in time and you want to visualize the movement between the observations. This can be used to visualize animal paths, vehicle tracks, or any other movement in space.

The following example shows a simple layer which contains 12 point features (3 for each id value).

Screenshot 2015-03-25 17.50.55

Using Time Manager interpolation, it is easy to create animations with interpolated positions between observations:


How is it done?

When you open the Time Manager 1.6 Settings | Add layer dialog, you will find a new option for interpolation settings. This first version supports linear interpolation of point features but more options might be added in the future. Note how the id attribute is specified to let Time Manager know which features belong to the same real-world object.

Screenshot 2015-03-25 17.43.08

For the interpolation, Time Manager creates a new layer which contains the interpolated features. You can see this layer in the layer list.

Screenshot 2015-03-25 17.46.13

I’m really looking forward to seeing all the great animations this feature will enable. Thanks Karolina for making this possible!

Today, I’ve released TimeManager 1.2 which adds support for additional time formats: DD.MM.YYYY, DD/MM/YYYY, and DD-MM-YYYY (thanks to a pull request by vmora) as well as French translation (thanks to bbouteilles).

TimeManager now automatically detects formats such as DD.MM.YYYY

TimeManager now automatically detects formats such as DD.MM.YYYY

But there is more: the QGIS team has released a bugfix version 2.6.1 which you can already find in Ubuntu repos and the OSGeo4W installer. Go get it! And please support the bugfix release effort whenever you can.

As I’m sure you have already heard, QGIS 2.0 will come with a new Python API including many improvements and a generally more pythonic way of doing things. But of course that comes with a price: Old plugins (pre 2.0) won’t work anymore unless they are updated to the new version. Therefore all plugin developers are encouraged to take the time and update their plugins. An overview of changes and howto for updates is available on the QGIS wiki.

TimeManager for QGIS 2.0 will be available from day 1 of the new release. I’ve tested the usual work flows but don’t hesitate to let me know if you find any problems. The whole update process took two to three hours … sooo many signals to update … but all in all, it was far less painful than expected, thanks to everyone who contributed to the wiki update instructions!


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