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Ilustračná snímka, dopravná zápcha na Prístavnom moste v Bratislave

SAS geographers studied the movement of people in and around the big city

19. 12. 2023 | 718 visits

The decrease of interactions with increasing distance phenomenon (the so-called distance decay) has long attracted the attention of researchers in various fields, including traffic studies, spatial planning and urban geography. We still have no satisfactory answers to basic questions such as how far do people commute within the city to reach different destinations? Are there potentially significant differences between different types of targets? The study by geographers of the Slovak Academy of Sciences attempts to at least partially answer the above questions through the analysis of the spatial differentiation of the "resistance of distance" to movement in urban space.

"In the study, we use signalling data from three largest mobile operators in Slovakia and present an original way of processing them into an O-D matrix at the level of population grid cells 1x1 km. A key part of the methodology was mainly the construction of algorithms for extracting the regular night and day location of individual mobile network users. By connecting the night and day locations, we obtained estimated movement vectors, which we projected onto the road network and estimated the distance travelled based on the principle of the fastest trajectory. The data prepared in this way made it possible to calculate the intensity of interactions and evaluate the nature of its decrease with increasing distance," explains Martin Šveda of the Institute of Geography SAS.

The results show the course of the "resistance" of the distance in the largest number of cells of the city grid. They are mainly located around the wider centre and in urban housing estates. The central parts of the city experienced little or no decrease in the intensity of interactions with increasing distance.

"The resulting spatial image produces unexpected results and suggests that the distance impedance increases from the city centre to its outskirts. On approximately 470,000 mobile devices located in the capital, we document that distance is not the only factor that affects the intensity of interaction. The location of the destination and its overall attractiveness are also important," added Martin Šveda.

The findings are close to the Newling theory, who found in 1969 that in an advanced stage of development, the area immediately adjacent to the city centre has a lower population density, which increases over a certain distance, creating a "crater" in the density gradient curve. Whether it is a universal phenomenon or just a specific functional structure of the city under study will be the subject of further research. However, mobile network data has enabled a view of inner-city mobility at a scale and scope that cannot be achieved with conventional data sources.


Spracovala: Monika Tináková

Foto: TASR/Martina Kriková

Graf: Distance decay, zdroj: Martin Šveda

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