| As a foundation for production and life, land resources are the basic materials for human living, optimal allocation of land use is an important way to alleviate the conflict between man-land system, also a vital measure to achieve the sustainable utilization of land resources.This paper focus on the study of Guangzhong in the Central Shaanxi Province based on the site observation data, DLG data, digital thematic map, remote sensing data and socio-economic data. Supported by the technologies of RS processing and interpretation and GIS system, the paper analyzes Landscape Pattern and the temporal dynamics of land use/cover in Guanzhong region, and uses regression analysis to study the formation of land use pattern. Based on that, six types of land resource optimal allocation programs have been proposed by employing the gray linear programming (GLP) model. Then the paper uses CA-Markov model to predict the land-use change, takes the land suitability assessment as basis, builds the simulation model of land use optimal allocation, and implement the optimal allocation plan in the relevant special unit. It also makes a land use regionalization based on county unit and finally composes a multi-level plan of land use optimal allocation.It is indicated in the research as following:(1) Land use in Guanzhong region has been greatly changed since 1985. During the study period, the areas of woodland, water, and construction land, have increased, while the unused land, grassland and cultivated land have decreased. What has increased greatest is the land for construction, which has increased 1391.106km2 during the past twenty years. The area of woodland has increased 233.378km2, and the area which has decreased most is cultivated land, which decreased 1560.779km. Most of the decreased cultivated land was changed to the woodland, grassland, and the area for construction. The decrease of cultivated land mostly occurs for the reasons of construction projects expansion, ecological returning to forest or grassland, and agricultural structural adjustment.According to the frequency degree and importance degree of land-use change, the following types commonly occurred from 1985 to 2000: the cultivated land changed to land for construction; grassland changed to cultivated land; grassland changed to woodland; and cultivated land changed to grassland. The types mentioned above embodied the direction of the land-use change in that period. From 2000 to 2005, the following types commonly occurred and embodied the direction of the land-use change: cultivated land changed to woodland; cultivated land changed to grassland; woodland changed to grassland; and grassland changed to woodland. According to the analysis about the land using/covering change of the two selected typical area (the Loess Plateau and the Guanzhong Plain), the cultivated land has decreased and the land for construction has increased. However, there are some differences for the driving force of cultivated land decreasing that returning farmland to woodland or grassland is the main reason for cultivated land decreasing in Changwu, followed by the expansion of the land for construction; the decreasing of cultivated land in Chang'an district which is a hot spot of urban expanding is mainly due to the rapid expansion of the land for construction.(2) It is indicated by the index of landscape level that: firstly, for the reasons of the increasing of the land for construction and its dispersive characteristics, the number of patches is larger and patch density (PD) of the land for construction is the largest; Secondly, because of the cultivated land occupied by the other land-use types, the original pattern has been damaged, which leads to the increasing of the fragile patches and the increasing trend of the patch density. According to the calculated results of largest patch index (LPI) and landscape division index (LDI), the cultivated land, woodland and grassland are the three predominant landscape types in Guanzhong region, however, with the improvement of landscape diversity, the degree of predominant decreases. According to the calculated result of mean patch fractal dimension (MPFD), the shape of landscape type tends to be simple, which can be understood as the effect of national policy and social-economic factors on the change of landscape. The landscape of Guanzhong region tends to be that landscape fragmentation process increases, fractal dimension generally decreased, and shape of patches tends to be simple. The decreasing of landscape diversity index of Guanzhong indicates that land use tends to diversified. Fragmentation of woodland and grassland decreased, especially a very large area of woodland and grassland patches play an important role on the preservation of ecological environment.(3)Based on grid data processing method, this study can be achieved the multi-source data fusion, which can supply data supporting for study. Several of land use types in Guanzhong region showed a strong positive spatial autocorrelation phenomenon. The spatial autocorrelation of the cultivated land and grassland was superior to other land use types, which of the unused land was the weakest. Within the scope of different distance, the differences of correlation were all obvious. With the increasing of distance, spatial autocorrelation index increased firstly and then decreased. By using classical regression and the space lagging regression models, the correlation analysis resulting of land use spatial pattern showed that the space lagging regression model based on the spatial autocorrelation of land use structure was better than classical regression model when it was used for explaining land use spatial pattern. Because some of the unobvious factors would be eliminated in space lagging regression model, and the main factors affecting the spatial distribution of various land use types were not the same.(4) The most suitable area of cultivated land, forest land, grassland and built-up land in Guanzhong region were 15219.81 km2,16281.48 km2,44909.66 km2 and 8348.34 km2 respectively, which accounted for 15.08%,29.62%,27.6% and 81.13% of all Guanzhong region of land. In this study, the basic scale of raster data in land suitability assessment was 100m×100m. Therefor, the minimum land plot for assessment was lhm2, which can be provided a basis for land planning and land management.(5) According to quantity allocation of grey linear programming and the spatial simulation results of CA -Markov model, the area of cultivated land in Guanzhong would continue to decrease, while the area of forest, grassland and built-up land would increase. In the process of optimization, the farmland adjusted to forest was mainly located in Qinling mountain and hilly-gully region of the loess plateau, which were, from the administrative units, located mainly in Longxian, Yijun, Xunyi, Hancheng, Taibai, Zhouzhi, Lantian and Tongguan, etc. Exploratory analysis method of spatial data (ESDA) was used for quantitative partition analyzing the importance patterns of social-economy and natural ecology in Guanzhong region of land use. The result was showed that the composite index of natural ecology in the southern mountains of Qinling and some parts of the northern loess plateau was higher than that of Weihe plain. The composite index of social economy in urban center as the center of Weihe plain was higher than Qinling Mountains and the loess plateau. Considering the coupling between the social economy composite index and natural ecology composite index, pattern of land use was divided Guanzhong region into five types:preferential development area, feasible development area, moderate development area, preferential conservation area and gray area. It can provide a basis for land utilization in Guanzhong region by the space simulation of land use optimal allocation and land use regionalization based on county scale.There are some progression and innovation in the article as follows:①The paper selected Guanzhong region as a study area, analysized the dynamic change of land use during the past 20 years systematically and comprehensively, and took a comparative study between Plain and Mountain on LUCC to discuss the differences of LUCC and driving force under different natural and socio-economic condition;②Spatial analysis of geographical information system was used for analyzing the pattern of land use. Comparison between the classical regressions and spatial lag regression was used for quantitative study, and then we tested the model's effectiveness by case study. The results showed that the model can be used to explain the formulation of land use pattern successfully;③Processing social-economic data based on administrative unit was weakly in GIS technology. In order to understand the affecting factors comprehensively, we used a multi-level land use optimal allocation program;④In the study about the land use regionalization based on county unit, we tried to adapt exploratory data analysis to analyze the pattern of land use and got a good results.
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