Measuring urban growth dynamics: A study in Hue city, Vietnam

The proliferation of urban sprawl has emerged as a prevalent occurrence in response to the rapid expansion of the worldwide population. The objective of this study is to determine the level of freedom for urban expansion using Pearson’s Chi-square (χ2) index and the amount of urban spatial dispersion using the Shannon entropy ( H n {H}_{n} ) index in Hue City, Vietnam. While the first index asserts the degree of freedom for observed urban growth above expected urban growth, the second index is applied to analyze urban spatial dispersion patterns through richness and evenness. Land use map data were collected from Japan’s JAXA agency from 1990–2020. Research results show that, in the past 10 years (2010–2020), the level of urban freedom expansion in Hue city has increased compared to the period 2000–2010 and 1990–2000, with corresponding χ2 values of 219.18, 150.05, and 106.95. The South-Southwest (TNN) area is also the area with the most significant urban freedom expansion among the eight regions in Hue City through three stages. The urban dispersion level in Hue City has also expanded recently when the H n {H}_{n} and H n ′ {H}_{n}^{^{\prime} } indexes gradually increased from 1990 to 2020. This result puts pressure on the Hue city government on how to develop the city sustainably. Therefore, the study also points out some disarmament to contribute to sustainable urban development.