Research And Software Development On The Basis Of The Graph Theory In Road Plane Design

The Road Plane Design is an indispensable part in the municipal engineering. At present, there are many problems in the road plane design of the civil engineering aided design software in our country. These software pay an important attention to geometric calculation, ignore the data structure; emphasize single line, no system, ignore the design of the road network, they solve the"zonal"problems instead of converting them into"network"problems; emphasize main line, no assisted line; In these software, the objects of graph are simple,no hypostatization, and there is no correlation among them, also no transverse or vertical constrain, moreover, calculate slowly, the rate of error is high.Therefore, a new model should be set up to solve problems above. This paper described the research and application of graphic and constraint model in the road plane design systematically.The innovations of this article are as follows:1,The research of line segment: to control the accuracy of spiral, the remainder of general formula of it can be controlled arbitrarily in the backstage; break through the traditional limit of maximum deflection angle of spiral, which is 180 oC, and set it at the degree of 900 oC; the algorithm of all kinds of spiral was improved further in the road plane design;2,The establishment of model: constraints model was set up based on graphic theory, break through the traditional static geometric model, meet the needs of dynamic design and re-design;3,The thinking of programming: using the combination of latest concepts of computer programming (Process-oriented programming→Object-Oriented program- -ming→generic programming),STL,BGL and computational geometry library, break through the traditional concepts of Object-Oriented, improve calculation speed, and establish a multiple-oriented CAD platform;The results of research on this subject have a strong practical significance: the in-depth study of line segment meets the need of the design of municipal engineering, and as a result design precision was improved; constraint model based on graph theory will greatly break through the bottleneck of expression of domestic municipal software, meet the needs of dynamic design and re-design. And at the same time it will promote the further study of the theory of road design.