When spatial interpolation matters: Seeking an appropriate data transformation from the mobile network for population estimates

Abstract

Analyses utilizing mobile positioning data rarely provide an exact method of data transformation to target spatial units. A common reason is likely the fact that researchers have already worked with spatially aggregated data prepared by the mobile operator or processing company. The article demonstrates the critical importance of employing an appropriate method to transform data from the mobile network into target spatial units, ensuring the precision and accuracy of the results. By evaluating ten different methods of data transformation from the mobile network topology to a population grid of 1 × 1 km, the optimal transformation has been sought. The most promising results were obtained through the methods using auxiliary information. While a dasymetric transformation utilizing building volume as the ancillary layer proved to be the most accurate, the utilization of free data from the Global Human Settlement Layer project also exhibits encouraging potential. Frequently used interpolation methods such as point-to-polygon (the user's location is considered to be the same as the base transceiver station's position.) or areal weighting are in fact the least appropriate methods of data transformation at a subregional level.