运用RS、GPS和GIS技术进行大比例尺土地利用动态监测的实验研究

土地利用数据的更新是土地管理工作的重要内容之一。依靠常规的手段不仅更新速度慢、难以主动发现变化区域，而且成图周期长、误差大。依靠遥感（RS）手段可以主动快速地发现变化区域，运用差分GPS技术可以精确获取土地利用变化的数量和性质，GIS则是管理土地利用的图形数据和属性数据（如土地利用类型、权属、图斑号等）的有效工具。基于RS、GIS和GPS的集成技术建立面向工程目标的土地利用动态监测新方法是本文研究的内容。

New approach to land use dynamic monitoring using remote sensing and GPS and GIS technologies

The dynamic monitoring of land use is an important routine work of land managers. Generally speaking, it consists of five components: ① actively identify the changes of land use; ② accurately and rapidly collect the spatial and attribute data of changing areas; ③ automatically update the land use spatial database; ④ computer based manage and organize land use information; ⑤ query, visualize and map the land data. Unfortunately, in most areas of China, land use maps are updated in traditional manual way, in which paper and cards are main media for data representation. Obviously it lacks flexibility in data management and needs a long term mapping period. Secondly, in traditional way land use change can’t be identified actively. Furthermore, it is time consuming and cost consuming in routine surveying ways. In order to satisfy the practical use, a new approach to dynamic monitoring of land use change is proposed based on the integration of RS, GIS and GPS technologies. Remote sensing technology, which has made great progress in many applied fields, can provide an efficient means for active identification of land use change. Because the resolution of remotely sensed data is not enough for mapping land use map at a large scale, differential GPS is necessary for accurately collecting change data in the field. The GPS receivers Magellan ProMark X-CM are selected to organize differential GPS system, which includes one base station and several mobile surveying GPS receivers. Considering cost, those data GPS received are based on post differential processing way, not real time kinematic. The error of post processing data is less than 2 meters, so they can satisfy mapping requirement at 1∶10 000 scale. By integrating both RS and GPS data into GIS, change data layer can be created. By means of spatial analysis tools of GIS, the change layer can be overlaid with historical land use data, and dynamic change information will be abstracted. This approach to dynamic monitoring of land use is a fully digital operation, so it makes best use of computer and GIS to manage, display, query and map the land use data. In our pilot area of Jiaoqu County in Inner Mongolia, the procedure is established and carried out. Compared with the traditional way, our new approach saves time about 60% and labors 50%. The resultant data collected by GPS are more accurate than those collected in traditional way. The users are very satisfied with our research work and they decided to adopt this new approach to accomplish the annual land use dynamic updating of Baotou City.