Application of Remote Sensing
Technique in Taiyuan Municipal Enivironment Survey Huo Yu lin, Dong Yu yang
Shanxi Remote Sensing Centre, Taiyuan, China Abstract As basic from of the space structure of human society, cities occupy an extremely important position in the development of social economy and history. In order to probe the scientific method of applying the remote sensing technique to the municipal environment survey as well as open up the service area of the remote sensing technique, a sythetical survey of municipal environment was carried out in Taiyuan district during the period of 1987 to 1989 which has yielded results in 28 items covering 8 fields . The data acquired through the investigation on Taiyuan’s background and status provides a decision making for the municipal management and plan. Introduction Taiyuan as the centre of Shanxi, China’s base of energy resources and chemical industries, boasts a natural deposit and highly developed mining trade. In 1949 Taiyuan was no bigger than 30.11km2 with a population of only 210,000 though it had a long history of over one thousand years. Great changes took place during the last forty years. In 1980 , taiyuan was up to a size of 133.63 km2 while its population became 1.14 million. Owing to the lack of water resources, and the serious environmental pollution, it becomes an important problem for the government in decision making as to how to control the development scale, exploit and utilize land and resources. The data acquired through common technical method prove to be not quite reliable partly because of the long period, and partly the differences in synchronization and comparability. With a view of raising the scientific level in municipal planning management and decision-making, Shanxi provincial government decided in 1987 to carry out a municipal environment remote sensing survey in Taiyuan. Technical Method 1. Design of the Survey According to the characteristic of the city, the survey should include background factors as regional geological structure, mineral resources, water resources disaster liability, environmental temperature field, and present situation as land utilization, building distribution, functional layout greenage ccoverage, environment pollution, tendency of development,...etc. The design and of the multipurpose investigation concemed scale,timephase , resolve rate and spectrum wave band of remote sensing data; Standard of classification, data precision, statistic model and map formation requirement of various essential factors. 2. Acquisition of Data The scope of surveying for background study is comparatively wider. The Land sat 5 TM data and NOAA 9,10 thermal infrared data prove to be appropriate. For present situation survey, the colour infrared ray, multispectrum, panchromatic black and white aerial photo, scales between 1/3800 and 1/50000, are selected. To study the evolution of a city aerialphotos of different time phases and the corresponding ground data are also used. For accuracy’s sake, also collected are topographic maps of corresponding scales, municipal overall plan, construction norm, statistic almanac and observation data from various stations. 3. Information Extraction Information are extracted through the classification based on aerial remote sensing material. For status quo information, as the classification is extremely elaborate. Take land use as an example, it is divided into 93 categories. In this case, visual interpretation is used. 4. Setting up a data Base Taking into consideration the specific need of the municipal management and planning a more detailed classification of data seems necessary. Original interpretation is stored through digitizer into data base of geographical information system. The next step is to develop software modules to do data processing in accordance with different needs of the customer. 5. Insurance of data precision Errors caused by common remote sensing interpretation are put under control through the direct judging and marking on the photo image maps. In addition through the constant sampling computer software error inquiry and field check, data precision is fully guaranteed. Main Contents of Tijuana Remote Sensing Survey The comprehensive remote sensing survey of Tijuana municipal environment emprises 28 subitems 8 fields they are
Benefit from the Taiyuan Environmental Remote Sensing Survey This survey took 2 years to complete. Participating in it are more than 60 persons from 17 branches and institutions. Practical amount work for each sub –item variers from 3-6 months positive results have been sent for use to departments as municipal construction, land, seismology and public security . It has drawn the attention of the decision making persons in the government. Multi-purpose flights were carried out. For the investigation on the remodeling of city small district , remote sensing survey took only half month to complete whereas in the past practice, by it took half a year smapling method. All the above serve to conclude that remote sensing survey is a technical method which has quicker speed, higher precision and better synchronization. Judging from the point of view of the social benefit, as remote sensing survey has a wider and richer content, it’s appropriate to join the efforts of various professions, subjects and branches through technical cooperation, thus minimizing differences of understanding while depending the degree of study. Practice proves that the application of remote sensing technique to the municipal planning and management is not only workable, but also very economical. In spite of the rich fruits reaped in the application of remote sensing technique, this is merely a first step try. We sincerely expect comments from our colleagues. |