The Research Of Automatic Drawing Isonline Generation Algorithm And The Application In State Of The Water System

With the rapid development of computer technology, research and drawing of isoline has be applying to wide range of areas, particularly in the field of Flood Control System, isoline map has been wide applied chart.The so-called isoline map drawing is the process of interpolation with mathematical methods and converting points with the same value into chart, using large number of discrete and regular physics or geometry data in two-dimensional plane. It is the combination of data and figure, so that technical staff can easily find the trends of changing data, get the results of computer simulation intuitively. As a method to reflect value change, isoline was widely used in modern scientific research, and is a common and effective expression method, particularly in the flood control system this method is widely used. Through isoline map, you can have a very intuitive understanding of real-time rainfall information.Chongqing Water Management System(hereinafter referred to water system), is the Chongqing Municipal Hydrology and water Resources Survey information construction of an important project. The project is in line with the Implementation of eight digital code software , and further enhance the efficiency of hydrological data processing and hydrology monitoring. The project should be an advanced, efficient, highly integrated software , covering current hydrological stations' single function what based on five digital code software. The specific contents include management, handling of message, Operating on duty, data query, moisture statistical and analysis, messaging platforms, PA calculation and forecasting. Statistical analysis and forecasting subsystem mainly draws up the isoline,reflected Chongqing's real-time rainfall information, real-time realizes the rain state of the water information inquiry accurately. In the flood season, the relevant government departments need to carry out effective analysis through immediate understanding of real-time rainfall information and the enquiries of related historical data, so as to make a prediction to ensure that accurate and timely treatment to reduce or decrease the impact on economic construction.induced by disaster weather . So, as a key part of flood prevention system, it is important to lively and intuitively reflect the temporal and spatial distribution by graph, convenient analysis spatial data, and accurately forecaste the flood state.There are many isoline rendering algorithm at the present time, including discrete data interpolation and fitting, the calculation of equivalent points, contour tracking, abnormal control in the tracking, the filling of the regional equivalent and so on. Although A lot of research has been done with the isoline drawing, the treatment about boundary issue has not relatively mature algorithm yet, so the precision of isoline map is limited.Giving the terrain and rainfall conditions in Chongqing, a isoline mapping method is propose based on the previous studies. The new way what apply to hydrological system can draw isoline map automatically. It is a innovation to approache the boundary line gradually using the method of triangulation to deal with boundary issues, process boundary of fitting isoline and achieve hot point enquiries.