Research On The Space Distribution Features Interpolation Method Of Trace Metal In The Offshore Water Environment Based On GIS

With coastal wetland water environment further requires that we draw a larger scaleregional present water environment. Spatial distribution of trace elements in coastal sedimentsreflect the environmental quality of land-related sea area, the study of environmental issignificant to protection and resource development for the region, the need for a large numberof on-site sampling, but a wide range of research is difficult to implement, and the cost is toohigh; present, on the basis of spatial distribution by sampling survey conducted on spatialinterpolation method to solve this problem.Using inverse distance weighting method (inverse distance weighted, IDW), tensionspline method (tension spline, TS) and ordinary kriging (ordinary kriging, OK) spatialinterpolate the synchronization extractable Leizhou Peninsula coastal sediments trace metalsdate based on GIS spatial analysis module. we use independent validation data set,cross-validation method and analysing the interpolated image to preliminary select the bestinterpolation method.In the absence of the expected accuracy of the interpolation results were the followingattempts: dividing the interpolation zoning and merging the integration raster resulting so asto effectively eliminate the negative territory of the Cd, Cr interpolation result by TS;improved the OK interpolation result of V precision by increasing normality V data; throughthe use of the maximum, average and minimum quadratic regression equation developedbetween the measured value and the estimated value, and grid computing. This method wasfound that Al which is the higher mean relative error (mean relative error, MRE) achievedbetter results, and effectively eliminated the smoothing effect which arised by OK.As the sampling points for the arrangement of the problems, we make some suggestionsfor the following five areas: the sampling point density degree, avoiding banding effects,determine and select the sampling method, sampling scale, secondary data selected. In thefuture, for the coastal wetlands of the same type of large-scale investigation of LeizhouPeninsula, we recommended using geological sampling method, combining the artificial rulesof distribution with random distribution and avoiding simple horizontal and vertical linear distribution. The interval between the sampling points should be within2.5Km.The following is the12kinds of trace metals interpolation results: There are eight kindsof trace metals (Al, Co, Cu, Mn, Ni, V, Zn, As) resulting graph is obtained by OK; There aretwo kinds of trace metals (Fe, Sn) resulting graph is obtained by IDW; The results graph ofCd utilization of the TS and OK; The results graph of Cr utilization of the TS and IDW. Thelargest MRE is the V which value of145%, the smallest is the As and the MRE was21%.All kinds of trace metal results MRE were less than150%and are all achieve the desiredaccuracy goal.