Kunming Soil Erosion Influencing Factors Analysis And Database Design

KunMing is one of the regions where the soil has been seriously eroded in China. The whole area of soil erosion amounts to 9,137.84 square kilometers, occupying 43.49% of the whole territory area. The soil-erosion leads to the land degeneration and the ecological environment worsening, so it is a significant ecological environmental problem the city faces. Many factors can influence the soil-erosion, and it occurs in a big space. Furthermore, many different data are demanded, but the data of soil-erosion is numerous and in no order. The database can express, store and manage some kinds of spatial information related to the geography space with the use of specific information structure and the data model, in order to meet the different requirement users hold towards the space information. In order to understand comprehensively the present situation of the soil-erosion, and the progress of ecological building in the conservation of water and soil, we use the GIS database to store data. Therefore, the dynamics can be reflected in these accurate data, which can provide scientific basis for the national decision-making. We discuss the database from the following aspects.We discussed all kinds of factors that affect the soil-erosion in Kunming. These factors include natural and man-made ones. Natural factors include climate, vegetation, edaphic factors, terrain, geological and hydrological factors. However, the main factors include rainfall, the degree of vegetation coverage, the soil texture, the terrain gradient and the ditch density geological lithology. As far as the mountain district Kunming is concerned, the man-made factors mainly include unreasonable use of land, the terrace, forest felling, mines exploition, roads building and so forth.We designed the Kunming soil erosion GIS database. The database involves climate, terran, geology, vegetation, hydrology, disaster and basic geography data. These data are divided into the attribute and the spatial ones. We established the metadata of the attribute data and the spatial data. Also we make conceptual, logical and the physical design separately on the Kunming soil erosion GIS database, and we specifically elaborate the management of the spatial data.We theoretically discuss the whole frame of the Kunming soil erosion GIS database. To adjust to the development of the economy and information, we use three overheadding constructions to build the distributional GIS database system structure. The design mainly focuses on the construction, of the database from four aspects. First, it is a system structure. Second, it is the model of local spatial data. It emphasizes on the analysis of the spatial data and the research of the data model in local area network. Third, it is the model of the universally spatial metadata. It emphasizes on how to unify the metadata object model and metadata model in different local spatial data model. Fourth, it is the model of universal spatial data. This is the spatial data model which is proposed by OGC. Here, we mainly consider its effects in the Internet environment.