Applications of Remote Sensing and Geographic Information System in China in china’s Land Survey, Evaluation and Administration
Li Bo-hend
Institute of Land Survey and Planning, PRC
Abstract
China has a large population and less land, the contradiction between population and land is getting sharper. The paper mainly discussed the applications of remote sensing technology and Geographic information System (GIS) in land science. China has more than 2800 county level units of detailed land survey and more that 1500 of them have begun the land survey task. The paper also introduced the applications in dynamic monitoring of land use, land evaluation and population capacity research: Remote sensing technology and Geographic land evaluation and population capacity research: Remote sensing technology and geographic Information System on establishing data base of land administration, multipurpose planning for land use, data base of paid alienation of land, evaluation of low yield land and unexploited land, monitoring of land disaster, automatic mapping of land use will be described.
Introduction
China has a large population and less land, contradiction between increase of population and decrease of land is getting sharper and sharper. Cherishing and properly using every inch of land and conscientiously protecting farmland is one of national policy that our country must persist in. In order to use limited land resources scientifically, it is needful to use advanced scientific technology-remote sensing, information technology, system engineering, bioengineering etc.—to construct our land science on the level of high technology and new technology.
State of Application
After establishment of the state land Administration in 1986, we began to adopt remote sensing technology and Geographic information system, and yielded good achievement in some district. Followings are four main aspects.
1. Applications of Remote Sensing technology in Detailed Land Survey In china
The detailed land survey in China more than 2800 country units. They conduct field survey mainly using aerial photo and space photo. Land use types were divided into 8 first class category, 46 second class category, and some counties needs add to third class. Mapping scales were divided into five types: agricultural zone is 1:10000, forest zone is 1:25000, half agricultural and half pastoral zone is 1:50000, pastoral zone is 1:100000, high mountain and desert zone is 1:250000. In land survey, new data of 1980s must be used if possible. In order to save funds,
white-black aerial photo majority of areas should be used. When conducting field survey, must draw boundary of polygons, political boundary, and linear surface features, and measure width of linear surface feature and areas of small surface features. Because aerial photo is rich in content and contains a mass of information we can differentiate various kinds of land use types with reliable quality.
Through land survey in Shenzhen city and Baoan country, the amplified multispectral color aerial photo was used. Multicolor has a good effect and rich in information. We can conduct the survey by combining indoor interpretation and field check on the basis of establishment of multispectral color mark interpretation key. We can project and copy factors of field survey to polestar membrane, then scan and digitize the graphic information with drafting scanner and transfer vector data into raster data, then calculate with software of ARC/INFO. Adopting of the new technology, not only brought preponderance of multispectral aerial remote sensing into play and improved the quality of land survey, but also used characteristic of data processing of information system and improved the accuracy of area measurement and calculation.
Color infrared aerial remote sensing technology was used in through land survey in Tianjin city, Lushan county in Jiangxi province, Hainan province, Ningcia Hui Nationality Autonomous region and some other cities and counties. In order to warrant the accuracy, we generally adopted aerial photography, with the scale from 1:25000 to 1:30000. Color infrared aerial photo is rich in color and contains a mass of information, it is needful to establish different interpretation key in different area. After training, the staff of detailed land survey can classify land use types skillfully. Applications of color infrared aerial photo in detailed land survey improved accuracy of land classification.
Tibetan plateau is sparsely populated and transportation condition is very poor. Expect detailed land survey in valley of Yarlung Zangbo river and Lasha river, which was conducted using color infrared aerial remote sensing, the detailed and survey in remaining one million square kilometers was conducted using TM and MSS image. Under the planning and organization of region state administration and the support of Institute of Remote Sensing, the Chinese Academy of sciences, the staff have already checked and accepted the indoor and field achievement of detailed land survey all over the region, and provided experience for detailed land survey in western district of our country- provinces and regions like Qinghai, Xinji ang, Gansu, Sicuan, Yunnan, western inner Mongolia etc. Total area of survey in tese provinces and regions mentioned-above are three million square kilometers. Detailed land survey in these provinces and regions is difficult because lack of synchronous data. Sicuan Land Administration made an experiment of detailed land survey in Ruoergi district using TM image of 1980s. Land administration of Xinjiang Uygur Autonomous Region and Institute of Agricultural Engineering of China made an experiment of detailed land survey in Ruoergi district using TM image of 1980s. Land administration of Xinjiang Udgur Autonomous Regions and Institute of Agricultural Engineering of China made an experiment of detailed land survey of pastoral zone onyiwu cornty using TM image (scale is 1:100000). The Institute of land Survey and Planning of China made an experiment of detailed land survey using space photo of soviet Union. Three experiments described above indicate that TM image and space photo of Soviet Union can meet the needs of detailed land survey in western pastoral zone, high mountain zone and desert zone.
