Using Symbolic Data in Gravity Model of Population Migration to Reduce Modifiable Areal Unit Problem (MAUP)

Abstract

Spatial analyses suffer from modifiable areal unit problem (MAUP). This occurs while operating on aggregated data determined for high-level territorial units, e.g. official statistics for countries. Generalization process deprives the data of variation. Carrying out research excluding territorial distribution of a phenomenon affects the analysis results and reduces their reliability. The paper proposes to use symbolic data analysis (SDA) to reduce MAUP. SDA proposes an alternative form of individual data aggregation and deals with multivariate analysis of intervalvalued, multi-valued and histogram data. The paper discusses the scale effect of MAUP which occurs in a gravity model of population migrations and shows how SDA can deal with this problem. Symbolic interval-valued data was used to determine the economic distance between regions which served as a separation function in the model. The proposed approach revealed that economic disparities in Poland are lower than official statistics show but they are still one of the most important factors of domestic migration flows. Ar. mean = 3.75 Ar. mean = 3.75 Ar. mean = 3.17 St. dev. = 0.93 St. dev. = 1.04 St. dev. = 2.11