GISdevelopment.net ---> AARS ---> ACRS 1990 ---> Poster Session Q 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. 2. Applications in Dynamic Monitoring of Land use Due to rapid development of China’s economic construction, each type of land use changed with extent –expanding of residential area, construction of transportation network, opening up of irrigation and drainage ditch, construction of farmland protecting forest zone, digging of fish farm etc. In order to meet the need of working out of state economic plan, it is needed to monitor land use dynamically. There are two methods. 1) Statistical data base of land registration Land administrator count actual change of land use and report to higher body according unified demand of statistics table. In order to improve the accuracy, accelerate the speed and warrant the quality, cadastral department of State Land Administration and Peking Normal University designed micro-computer software for statistics of land registration. It adopted unified standard of classification and unified data structure. Input data into micro computer and establish statistical data base of land registration on the basis of completing city and country level statistical table. Application of this kind of software raised benefit and warranted accuracy of the number. Another method of dynamic monitoring is: land administrator indicate change of land types and tenure in land correctly on the existing land use map according to change of each polygon, then measure and calculate areas, classify, count and pool for completing the detailed land survey. (2) Conduct dynamic monitoring of land with TM image In the experiment, we selected space photo of three phases: MSS image of 1979, TM image of may, 1984 and TM image of April, 1988. The experiment work was carried on according to following procedures: select the 1:10000 topographic as a control map and conduct geometric calibration with the images of three phases. Select the training area outdoor and analyses pectral characteristic of different land use types and establish the standard of computer classification establish Digital elevation model of experiment area Conduct automatic classification with image processing system conduct complex analysis and distinguish the changed land use polygons and unchanged land use polygons. field check and acceptance The experiment indicates that dynamic monitoring of land use and crop distribution using TM image is effective, especially in distinguishing linear surface feature—for instance the effect is apparent for newly constructed highway, ditch and newly digger fish farm, newly extended vegetable plot etc.. In Beijing area, we can clearly distinguish distribution of winter wheat, two stubble land of wheat and maize, maize and vegetable plot through comparing space photo of April and May with that of August and September. This is the advantage of analysis multimoments of TM image apply only to macroscopic dynamic monitoring of land use and distribution of crop because the resolution of TM image can not meet the need of detailed land survey in agricultural zone yet. 3. Applications on Land Evaluation The purpose of land evaluation has two aspects: one aspects is to serve the land use planning and carry on evaluation of land adaptability; another aspect is to serve paid alienation of land and carry on evaluation of land economy. All of these two methods needs guarantee of reliable data, needs to establish data base of land evaluation and linear model of land evaluation. it must design special software in micro-computer to conduct digital analysis. For example Sicuan Land Administration selected 11 relatively stable factors, which has relatively great effect on paddy field evaluation, and these factors are accumulated temperature (>=10degress centigrade), clay content, soil organism, total nitrogen, total phosphorus, quickacting phosphorus, bioclimatic potential, exchange capacity, irrigation rate, soil thickness, total phosphorus, bioclimatic potential, exchange capacity, irrigation rate, soil thickness, total potassium ect.. The quality of land evaluation was improved because the date is scientific and the method of quantities analysis is reliable. 4. Research of Land Population Capacity Use and Productivity Assessment of China The Institute of Land Survey and planning of china has been conducting research of land use and population capacity assessment of China in collaboration with Heliongjiang Land Administration and Jiangsu Land Administration since 1989 under the support of FAO of United Nations, The scale of country level research is 1:5 millions and the scale of provincial level research is 1:500000 or 1:1 million. Whole research was divided into four steps: Inventory of land resources Evaluation of crop adaptability Calculation of potential of land productivity Calculation of population-capacity First of all, It must complete five kinds of basic map—map of administrative divisions, soil map, map of thermal zone, map of temperature growing period, map of moisture temperature in growing period: then input above –mentioned data into computer with software ARC/INFO and process the data with software of Pumps and Erdas. After conducting complexes analysis of soil and climate generating site of land ecology, establishing data base of land. Then conduct evaluation of crop adaptability and potential of land productivity; as well as design optimum model according to low level input, intermediate level input and high level input. After introducing nutrition level on the basis of evaluation of potential productivity, it may predict the population-capacity of land. Prospects of Applications Along with deepening of land administrative work of china, applications of new technology and high technology will develop further followings are seven main aspects. 1. Establish Data Base of Land Administration The purpose of establishing data base of land administration is to establish four level data base (country, province, city and country), taking land survey, cadastral survey, various kinds of land administration of the state and image of remote sensing as the sources of information, provide accurate of data guarantee for construction of national economy, modernized land resources administration such as land planning, land development, land renovation and paid alienation. There are two types of data base: statistical data base and spatial data base. State land Administration have already designed micro-computer software of detailed land survey, which can complete orthographical rectification of single aerial photograph and automatically draw land use map. In the meantime, the State Administration is designing software cadastral data base. 2. Establish Data Base of Paid Alienation of Land The data base of paid alienation of land consists of four parts data base of land price formulating—formulate reasonable land price for each stretch of land according to overall plan data base of investment of foreign businessman—input the information of foreign businessman and enterprises (e.g. capital, commercial credit, sum of investment, purpose of investment, purpose of using land, the number of using years, benefits of product etc) into computer data base of land price information—establish land price data base with land price information from the world and various special economic zone in China. data base of land policy, statute and rules—in order to implement system of paid alienation of land, input and save China’s law , policy, statute and rules concerning land affairs as a legal basis of paid alienation of land. In which is mainly statistical data, The information of alienated land in special economic zone on shenzhen, Xiamen, Fuzhou, Hainan, Shanghai Tianjin etc. have already been inputted into computer. 3. Multipurpose Dynamic Planning of Land use There are two kinds of overall land use planning: planning of natural area planning of administrative area. Multi-purpose planning is established on the basis of multi-factors and multi-variables. Basic data is relatively stable, unique and has certain value. Multi-factors were assigned various values according to different period and different demand. 4. Evaluation of low Yield land and Unexploited land China lacks of farmland reserve, and in the meantime wastes a lot of land. For example, there are a lot of five –edge-land (side of farmland, side of village, side of road, side of river, side of lake) scattered plots unutilized land, waste land, clay beach, abandoned land and low yield land (low yield farmland. Low yield orchard, low yield water surface.) Experiment of survey of low yield land and unexploited land has been made in some provinces and regions,. the practice indicates that the method of combining remote sensing technology and on-the-spot survey has a good result. In the areas where through land survey was completed acquire various kinds of yield date through on-the-spot survey on the basis of existing data and map. In the areas where detailed land survey has not completed, it is needful to use latest remote sensing image to conduct survey. Scale of the image is 1:100000 and it can meet the needs of survey and evaluation of low yield land and unexploited land. 5. Research of Land Disaster Land disaster includes drought, flood, loss of water and erosion of soil, salinization of soil and desertification. Aerial remote sensing and space remote sensing are important information sources for land disaster. By adopting infrared and thermal infrared information and through correlation analysis of indirect factors and establishing dynamic model of thermal inertia of land, we can improve in accuracy of time, quantity, position, nature and correlation analysis of research of land disaster. 6. Automatic mapping System of Land Use Map China has launched detailed land survey over 1500 counties, and over 600 counties have completed, and has begun pooling in some areas. In four levels: county level, district and city level, province level and state level. The work is conducted from low level to high level. The work load of land use mapping is very large. If calculating with the scale 1:50000, there are about 3000 pieces all over China. It will need us 15 to 20 years artificially. In order to arrant the quality and accelerate the speed of, mapping we can use existing software of microcomputer. For automatic adopting and deleting, but it is needful to research comprehensive key to realize automatic generalization of linear factor and polygon factor.