Representing a territory of mobile individuals by calculating total stay-times

André Ourednik, Wednesday, March 30, 2011

Ratio between real stay-times and stay-times under the "immobility hypothesis"Counting how many people reside at a given address might just not be enough to understand a territory of mobile individuals. Instead of counting people, I count their “stay-times”. In other words, I sum up the time spent by people in each place.

The map above compares two results:

  • ΣH, the hypothetical total stay-time which would have been registered if people never moved.
  • ΣT, the observed total stay-time,  calculated from data of the Swiss Federal Population Census 2000, the hotel night counts and the transborder workers counts.

Both ΣH and ΣT are calculated in minutes. If ΣH of a commune is divided by the number of minutes within a year, we get the residential population of that commune.

The ratio ΣT/ΣH makes it possible to identify communes whose “population” is under- or over-estimated by standard census counts. They also make it possible to identify attractors of mobility. In effect, red areas have a larger population than suggested by a residents-count, because time is spent in them by people residing in other communes. Blue areas, on the contrary, have a smaller population.

The lowest ΣT/ΣH-ratios are registered for peri-urban communes. Obviously, people who sleep in these actually live elsewhere.

The highest ΣT/ΣH-ratios are registered in the cantons of Valais and Graubünden mountain resorts. In most extreme cases, tourists triple their population. Urban centers have “only” up to 30% more dwellers then resident-counts would suggest, but their ΣT/ΣH-ratios are systematically positive.

These population differences are important for many reasons, among which infrastructure costs. Shouldn’t peri-urban regions contribute more to the financing of urban centers?

Spatial data resolution: Swiss commune.

Time-data resolution: minutes.

Data handling tools: SPSS and Excel.

Mapping tools: ArcMap, ScapeToad (for the anamorphosis) and Illustrator.

Cite as: André Ourednik (2011) « Representing a territory of mobile individuals by calculating total stay-times » in Maps and Spaces from [Last-seen December 10th 2018].
Category: Maps

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  • […] what extent this is true can be verified by looking at “imported” stay-times I’ve already talked about in a preceding blog . Here is another illustration, based on hotel nights. As you can see can see on this map, the […]