国土数値情報を利用した土地利用形態の立地依存性の解析

宮崎県における事例研究

抄録

Both the natural and social environments affect land-use patterns. We analyzed their effects on current landscape structure in Miyazaki Prefecture, southern Japan. A digital land-use map with 8 categories (paddy field, other agricultural field, woodland, devastated field, building, transport filed, golf field and other land-use) provided in the National Land Numerical Information was used for the landscape analysis. Forty-five regions (9 cities, 28 towns, 7 villages and whole prefecture) in Miyazaki Prefecture were classified by the cluster analysis using proportion of each land-use into 3 landscape types : “Urban-farm type”, “Intermediate type”, and “Mountainous forest type”. This classification was well corresponded to the average elevation and slope of the regions. Among the four selected regions for detail analysis, Miyazaki City and Kobayashi City were classified as the Urban-farm type, Aya Town as Intermediate type, and Shiiba Village as Mountainous forest type, indicating correspondence of the social environment with landscape types. Further analysis of these four selected regions, using Jacob's electivity index in relation to the natural environments, revealed clear patterns of land-use habit : high electivity for intensive land-use (buildings, paddy field, and agricultural field) at lower elevation and gentle slope classes, and for less intensive land-use (woodland) at higher elevation and steep slope classes. Influence of slope on electivity was more evident than that of elevation. The analysis also showed slight different patterns of electivity between the regions even for the same land use in the same natural environments. This indicated the possible evidence of varying electivity influenced by different social environments. We concluded these results that the landscape structure and its interaction with the social environment would have been developed under strong constraints of the natural environment represented by topography in the studied area.