A New Way to Simplify Error Handling with the TravelTime QGIS Plugin

Today we've released a new version of the TravelTime QGIS plugin with a new, easy-to-use feature that makes error handling much simpler. 

The new feature is called Robust Mode. When you're running an analysis with lots of points and the Robust Mode tool is enabled, it will still run successfully even if there are errors associated with some of the input points. 

Check out this video below explaining the new feature:

How does it work?

Robust Mode is available in all of the Advanced and Simple tools from the TravelTime toolbox. 

For example, here you can see it as a new tick-box option in the plugin's Time Map Simple tool:

When running a tool with robust mode enabled, any successful requests are saved and added to the map, even if other requests are unsuccessful. 

In previous versions of the QGIS plugin (or with robust mode disabled in v1.7), any unsuccessful requests will cause the whole tool to fail and no output is generated, even for successful requests.

What does it look like in action?

In the example below, we’ve got a handful of locations across the UK, and we want to create a 60-minute driving isochrone around each one.

To do this, we’re going to use the Time Map Simple tool. First, let’s see what happens when we run it with Robust Mode disabled. 

After running for a few seconds, the tool returns an error:

Reading the error description, it sounds like one of the points in our input layer is not reachable by car, and so an isochrone cannot be created around it. This may be because one of the points is on a body of water, or is in a very remote area and simply too far away from the nearest road.

As a result of this error, the tool has failed and we have no new output layer added to the map.

Now let’s run the tool with the same parameters, but with the Robust Mode tick box checked:

This time we still get an error (which is to be expected as the unreachable location will still be unreachable!) but there is an additional message letting us know that we have an incomplete result:

The other main difference is that we have a new output layer added to the map, with the isochrones around all of the points that were reachable:

It’s now easy to see that the point that was causing the issue is located in the North-West corner, near Liverpool. Zooming in, we can see that this point is indeed on a body of water, which explains why it was not reachable.

When should I use Robust Mode?

The new Robust Mode feature is available in all the Simple and Advanced tools in the TravelTime toolbox.

You should enable Robust Mode when:

1. You know that the analysis you are doing will likely include locations that are unreachable (e.g when using centroids of geographical areas)
2. You have tried to run your analysis with Robust Mode disabled, and have received an error

How can I upgrade to the latest version of the TravelTime QGIS plugin?

To upgrade to the latest version of the TravelTime QGIS plugin (v1.7), simply click Plugins from the top navigation in QGIS, then Manage and Install Plugins

Search for the TravelTime plugin, and click the Upgrade plugin button.

Improve your location analysis with the TravelTime QGIS plugin

The TravelTime QGIS plugin includes a range of tools to help you gain unique location data insights.

You can use the TravelTime QGIS plugin to:

• Create isochrones (travel time maps)
• Calculate travel times between thousands of origins & destinations
• Filter points of interest within a travel time area

To learn more about what you can do with the TravelTime QGIS plugin, check out our documentation or get started for free.