The comprehensive analytical mapping on the Chinese territory satelite
Fu Suxing
Institute of Geography, Chinese Academy of Sciences
Beijing,China
Abstract
The article mainly expounded the Territory Satellite images mapping characteristics and the technical standards for the applications. Because the images got with the scanning angles of + 42 degrees, which can generally be used for thematic series mapping and can accord well with the precises demanded. The article has analyzed the comprehensive applications of multiple information, such as the thematic series mapping on the hydrology utilization of land resources, agricultural fields with middle-low yields , forest resources ,tourist resources , changes of natural environmental elements, regionalization of pre-Cambrian metamorphic rock, and evaluation of regional engineering stability. The practical investigations show, that the Territory satellite images combined with other remote sensing data is a new technical method for us to draw the analytical thematic maps at high level.
The Territory Survey Satellites (Territory satellite) were lunched in October 1985 and October 1986 respectively, and the territory images covering all-over the country have been acquired. The thematically application studies have been conducted by selecting more than ten typical regions including the Beijing-Tianjin-Tangshan region, the Huanghe River delts, etc. The various achievements have been gained by the studies on these regions. This marks that the aeronautical and remote sensing technology of China has reached a new level and has the capabilities to serve the nation in land reclamation and national economic construction. Starting out of practical use, the application studies of the territory images of resources and environment in the Beijing-Tianjin-Tangshan region have overcome the restrictions of specific thematical investigation, have studied the various thematics and conducted the series mapping at scales of 1:250,000 and 1:500,000. Meanwhile, the related databases have been set up.
Researches on the territory images and their mapping charateritics
The panoramic images acquired by the low-orbit Territory Satellites of China have the merit features such as the high resolution, identified layers, etc. In the central part of the image the scale ranges between 1:200,000 and 1:230,000; around the central part outwards the scale gradually becomes smaller with the increasing satellite heights and scanning angles. The applicable technical standards have been proposed through the analysis of scanning angles, theoretical calculation and practical approval of sample tests.
Taking ±20 degrees as its scanning angle, they are the two zones on the two sides of the central part with a width of 45cm respectively. With small distortion and clear layers, they can be used for the thematic interpretation and, mapping at scales of large of medium. When the scanning angles are ±42 degrees, they are the images between ±21 ---±42 degrees. With relatively great distortion, decreased resolution and smaller scale, the images can only be used for the analytical mapping at a scale of 1:250,000. When the scanning angles fall between ±42--±60 degrees, it will be difficult the precise of thematic mapping, we have developed the geometric rectification software package that this combined the light beam method, the finite element method and with auxiliary parometers; we have researched the Territory satellite orthographic images of an extended region. Their rectification accuracy (with a mean error of about 55m for a point area) is more than one times than employing the multinomial method only.
