Research And Application On Some Key Technologies For Common Spatial Terrain Data Acquisition And Procession

Theoretical studies and application of Geographic Information System (GIS) are at a rapid stage of development, and GIS has been widely applied to land use, resource management, environmental monitoring, transportation, urban planning, economic development and other aspects. With putting forward "Digital Earth" concept, further impetus to the development of GIS as a technical support. Meanwhile, some scholars have bent themselves to correlative theoretic research, such as spatial apperceive, spatial data and spatial relation.Spatial terrain data is the basis of Geographic Information System and core. Extracting data from a variety of resources and become universal information space terrain data is the research and development of data acquisition. Combination of pattern recognition and digital graphics and video processing technology, image objective data extraction technology appears to be particularly important in geographic information system data acquisition and geospatial information automatically understanding.In this paper, some spatial terrain data are collected from where contour edge detection arithmetic extracts and next data processes. Profile on the verge of testing, a modified algorithm based on the Canny edge detection method, by which modifies the linear interpolation in non-maximal inhibition and improves amplitude calculation, is put forward to achieve a better edge detection. So in the same parameters, improved Canny algorithm demonstrates better edge continuity and noise suppression.Topology data is an integral part of data collection, through the line (arc) layer makes up of polygon layer. Based on this level, the author gives an arithmetic of patch (polygon) auto-construction by the azimuth turning left and the virtual arc vector external product, Azimuth turning left algorithm constructs polygons, and in order to solve the duplication and inefficiency of polygons, an algorithm of polygonal search direction is put forward that based sum of vector external product-based virtual arc, this arithmetic can estimate the polygon will turn left or right.In arc-polygon topological process, gives an arc topological judgment arithmetic that based on spatial fuzzy representation to judge arc and its left or fight polygon relation, following arc and arc join relation, looking forward all of polygon closed circle, and calculating the value of div to judge current polygon is left polygon or right polygon of arc. At last, the polygons have no data redundancy so they can represent levels between polygons. After constructing polygon relation and arc-polygon relation, region-construction and touch-construction are proposed as some special application. Region-construction is to acquire all polygon data in selected region. And touch-construction acquires the polygon data around touch position of mouse by importing principle of greed matching and temporary line level.Due to the level of theory and the limitations of this method, there are some problems, and it still needs to continue to improve. However, author believes that in the constant improvement of techniques, common terrain spatial data will be a major development direction of GIS.