The calculation of drive-time zones – also referred to as “isochrons” – makes it possible to organize your sales territories according to accessibility. Using this technique, you can easily produce tariff zones around your business sites or generate representations of turnover potential in your catchment areas.

Preparation

In order to calculate drive-time zones, your project file should contain a point layer with one or more locations (e.g., of your offices). Also make sure to include street layers in your project, i.e. select at least the highways and main roads sub-layers. For more detailed representations, select the minor roads and local roads sub-layers as well.

Calculation

Select Isochrons… from the Calculations menu. An application wizard will guide you through the subsequent steps. Select “Time to next location (min)” and click Next.

Make the following selections in the second dialog window:

In the upper left-hand corner, select the location layer that contains your locations – in the case of this example, this is the layer containing Frankfurt’s location.

Specify the name column under the Naming column heading. In the field directly below, select all of the line layers that should be taken into account for the purpose of the calculation. For a simple overview, it’s sufficient to select just the highways and main roads line layers.

Tip: The TeleAtlas street layers integrated into the application contain average travelling speed entries for every street segment. The shaded “average speed of 50 km/hr” entry is only used when no data exists for the average travelling speed of a given street/roadway.

The third dialog window allows you to designate the information that should appear in new columns in the street layer table. For the purpose of getting to know this feature, place a checkmark in every box and click Next.

In the final dialog window, you can specify the number of zones to be created as well as the zone boundaries in minutes.

The Create isochron areas option allows you to create a new layer that illustrates drive-time accessibility (see illustration on far right). Go ahead and select this option.

When you’ve entered your desired settings, click Calculate. Depending on the complexity of the data involved, this may take a few moments.

Result

The calculation will deliver two results:

In the layer tables of the streets you selected, you’ll find three additional columns containing entries on the exact distance, drive-time zone and name of the associated business location for each of the street segments in question.

More importantly, you’ll find a newly created area layer called isochron areas. This allows you not only to display drive-time zones on your maps, but also to carry out additional data manipulation (such as layer data transfers) and analyses, such as displaying the number of customers located in each distance zone.

Additional tutorials can be found at www.gfk-geomarketing.com/tutorials.