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Urban Expansion and Provincial Economic Convergence in Thailand: A Satellite-Based Rank-Size and System GMM Analysis |
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| รหัสดีโอไอ | |
| Creator | Wittawat Kadthan |
| Title | Urban Expansion and Provincial Economic Convergence in Thailand: A Satellite-Based Rank-Size and System GMM Analysis |
| Publisher | Phetchaburi Rajabhat University |
| Publication Year | 2569 |
| Journal Title | Interdisciplinary Research Review (IRR) |
| Journal Vol. | 21 |
| Journal No. | 4 |
| Page no. | 23-34 |
| Keyword | Zipf's Law, Gibrat's Law, Urban primacy, Regional convergence, System GMM, Satellite built-up data |
| URL Website | https://ph02.tci-thaijo.org/index.php/jtir |
| Website title | Interdisciplinary Research Review (IRR) |
| ISSN | 2697-536X |
| Abstract | This study jointly examines Thailand's urban size distribution and provincial economic convergence over 1995–2024, using multi-epoch satellite-derived built-up area for 77 provinces and gross provincial product (GPP) records for 76 provinces. Three empirical strategies correspond to three objectives: rank-size (Zipf's Law) analysis across six epochs, a test of Gibrat's Law of proportionate urban growth, and a dynamic panel System GMM model of GPP convergence. The Zipf exponent rises modestly from 1.158 (1995) to 1.206 (2020), indicating a stable but persistently primate urban hierarchy. Gibrat's Law is rejected (β = −0.0039, p = 0.010): smaller urban areas expanded faster than Bangkok, whose primacy index fell from 0.493 to 0.443. Cross-sectional beta-convergence in GPP is not significant unconditionally (p = 0.142), and urban expansion is only marginally associated with GPP growth (p = 0.064); however, once structural controls (initial population, agricultural share, distance to Bangkok, education) are added, the coefficient on initial GPP reverses sign and becomes significant (β = −0.0055, p = 0.012 including Bangkok; β = −0.0062, p = 0.007 excluding Bangkok, R² ≈ 0.26–0.28), indicating genuine conditional convergence. The System GMM estimate of GPP persistence is near unity (ρ = 0.997), implying a convergence speed of just 0.32% per year and a half- life exceeding two centuries. These results indicate that Thailand's urban system is deconcentrating physically, and that provinces are converging conditionally toward different structurally determined steady states even though absolute convergence is absent, with direct implications for secondary-city infrastructure investment and the use of open-access satellite data for subnational economic monitoring. |
