The extraction of continuous shoulder line of valley having precise location is the key technique to the construction of spatial distribution mechanism-course models such as soil erosion, sediment transportation and runoff course in gully area in the Loess Plateau. The extraction technique presented in this paper is a morphologically based method utilizing finite morphologic elements to define the topographical structure. In this paper, the authors present an algorithm by which the drainage network and the continuous shoulder line of valley is extracted automatically from the DEM of Wangjiagou in Lishi, Shanxi, which is located in gully area in the Loess Plateau, and the final result is in accordance with the real condition of the experiment area.
Based on the analysis on general features of regional sustainable development system, this paper discusses the superiority, potentiality and problems in the research of regional sustainable development using system dynamics, and proposes some concrete ways to resolve existing problems, at the same time, a method frame work of using and expanding system dynamics to research regional sustainable development is given.
Taking Lishu County as an example, this paper states the way of maize yield estimation of meteorology by gray model, which includes the methods to forecast the tendency yield by GM(1, 1)model, to figure out the dominant meteorological factors affacting meteorological yield through gray-relative-degree analysis, to foreshow the meteorological yield by GM(1, N)and so on.