| Since 1960s, GIS technology has been greatly developed and gradually introduced to many fields. Depending on improvement of geographic information technology, GIS is widely used in many fields of geography, such as productive evaluation of cultivated land, land suitability assessment, land resources management and planning. GIS also plays an important role in country land resources management. However, due to the diversity and complexity of land resources attributes, there are still some questions and limitations at present. Aimed at these questions in land resources management, this thesis mainly includes following aspects:(1) Based on components GIS, a better solution is found to the problem of empty attributes of polygons appeared after the combination of land use map and soil map. Through development, the system could combine and delete all polygons that below 10000 m2 under 1:50000 scale at one time.(2) Based on soil nutrient content, the system, adopting 3D expression pattern, can express the distribution of soil nutrient content more intuitively. Attributes processing system generates TIN data with mass points, which make nutrient content as its elevation value.(3) By using 3D controls, the system three-dimensionally displays the distribution of different soil nutrients content. At the same time, it can zoom in or zoom out at any rate at the map. It's more intuitive to display the distribution of soil nutrient content than the traditional method of two-dimensional expression. This method can also show the correlation of different nutrient contents in a macroscopic way. |
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