Design Of Geochemical Data Processing System GC-GIS Base On Fractal Method

Fractal geometry theory deepens and enriches the dialectic relation of parts and whole in a fresh lay. It offers a bran-new consideration on how to find the intrinsic rules and study spatial framework no matter it is randomizing or certainty.The fractal geometry theory was applied in geosciences'in the 80' last century. Researchers studied all kinds of geologic phenomenon in different fields and then get many productions. Fractal geometry used in geochemistry is quite early. It is mostly used in getting the threshold of geochemical anomaly.The solution of geochemical anomaly thresholds is one of the most important matter in geochemistry and it decides the prospect work succeed or lose as well. There is not a method that is mostly certifiable and most scientific by far. The traditional way of determining thresholds of chemical elements is based on the assumption that chemical elements are in normal distribution or element contents are continuously changed in space. Nevertheless, the spatial landscape of chemical elements is extremely complicated. Much research indicates that geochemistry elements distribution may be may be a chaotic system of low dimension. The background and anomaly values of elements usually show independent power index relationship, resulting in the multifractal distribution of chemical elements.Geochemical field often has its orderliness. Randomness sometimes alternate with certainty so it makes the geochemical anomaly more complex. Fractal geometry is mathematics means to solve this kind of problem. Therefore, the writer attempts to line out the geochemical anomaly using fractal geometry theory. Base on the theory a GC-GIS system is built with Visual Basic computer language, statistics by Surfer and spatial manage by MapInfo. It is founded on fractal geometry with secondary development as instrumentality, so it can make up the shortage of Surfer's spatial management and MapInfo's statistical counting. It is well used in the practical work.In order to validate the fractal geometry theory and try out the GC-GIS system, 6 kinds of geochemical data(Au,Ag,Cu,Pb,Zn,Fe) in Weichang area Hebei province are worked out respectively with fractal geometry and traditional method. The conclusion indicates the way using fractal geometry match the distributing of practice mineral well. Furthermore, advices are given on prospecting work in the area based on the conclusion.During the course of delimiting anomaly, the writer grades the elements(Ag,Au,Cu,Pa,Zn) isolines according to their mineral association in order to weaken the drawing effect of anomaly. That means makes the intense anomaly area overlap and then the anomalous difference is more salience. Since the final contouring map comes up with the normal mineral association, it is not only more persuasive but also fewer factors dropped.