Fractal Research On The Incised Meanders Of The Tuojiang River Based On Fractal Theory And GIS

The formation and development of the fractal theory opened a new mentality for the quota description of the landform characteristic and the non-linear research of the landform development and provided a new theory, method and possible research idea. While compared with other quite mature theories, the fractal theory had many imperfects points and a relatively strange domain to the majority scholars who were engaged in the geographic science research. At present, the major fractal research stayed on the stage of analyzing the fractal characteristic of geography phenomenon and the fractal dimension with quantification. Many questions such as fractal nature and mechanism questions are needed to be researched thoroughly.This article applied the fractal theory to conduct the research to the fractal of the incised meanders of the Tuojiang River’s. According to the incised meander, characteristics, the meanders of the Tuojiang River are divided into V-shaped, the U-shaped, Ω-shaped and the complex meander belt, total24incised meanders (belt). The article selected1:100000,1:200000,1:250000,1:500000and1:1000000such five scale topographic diagrams, acting the divider method and the box-counting method, calculating the fractal quantity by different survey scale to the Tuojiang River incised meander (belt) by linear regression.To the fractal research of the middle and lower courses of the Tuojiang River (from Huiakou of Jingtang County to Luzhou), the article used the topographic diagram of1:10000and the divider method to carry on the fractal demarcation and the analysis to the middle and lower courses of the Tuojiang River with1km,2km,5km,10km and20km such six different scales. The fractal dimension of the middle and lower courses of the Tuojiang River is1.206. This indicated the length of the middle and lower courses of the Tuojiang River exist the fractal characteristic, and the river’s bending strain was high, incised meander growth.To the fractal research of the Tuojiang River’s incised meander (belt), based on1:100000 topographic diagram, the research used the divider method, selected the scale sector which was500m,800m,1500m and2000m such six survey scales, analyzed the fractal characteristic of the Tuojiang River V-shaped incised meander, the U-shaped incised meander, Ω-shaped incised meander and the compound meander belt. The analysis result indicated these four types of incised meander all had the fractal characteristic. The incised meaner form was more complex. The bending strain is more great, the fractal dimension of the incised meaner was bigger. The article had made the comprehensive discussion to the fractal nature of the incised meander of the Tuojiang River. Firstly, research had analyzed the scale sector selection to the influence on the incised meander fractal. Based on1:100000the topographic diagram, the article selected sectors in7different scales and carried on the analysis of the incised fractal (belt) meander with the gauge law.The analysis result indicated that the fractal size had influence on the fractal analysis of the incised meander under the premise of the same figure source scale, the fractal dimension of the incised meander enlarged along with the scale increasing. Secondly, the article analyzed the influence of the topographic diagram scale on the fractal dimension of the incised meander. This paper selected topographic diagrams separately in1:100000,1:200000,1:250000,1:500000and1:1000000such five scale, carrying on the analysis and computation of the fractal dimension of the incised meander of the Tuojiang River by the same scale. The analysis result indicated that under the same fractal scale, the fractal dimension of different scale topographic diagram’s incised mender (belt) is existence objective. Thirdly, this paper analyzed different commensurabilities influenced on fractal dimension of the incised meander.The divider method and the box-counting method all may be used to calculate the fractal dimension of the incised meander, but the calculation result by these two methods had the difference. In the figure source scale and in the scale same situation, the fractal dimension of U-shaped, Ω-shaped and complex meander belt incised meander which obtain with the divider method is bigger than the fractal dimension which was obtained with the box-counting method. The fractal dimension of the V-shaped incised meander which was obtained by the box-counting method is bigger than the fractal dimension by the divider method.The growth of the incised meander of the Tuojiang River is the typical representative of researching the incised meander. The fractal nature of the incised meander of the Tuojiang River was existence, but the fractal dimension was a relative value. It changed with the difference of the map scale, the scale and the quantity calculated the method. The fractal dimension of the incised meander may not compare blindly.