Forest Distribution-Oriented Study On Data Model Of Abrupt Change And Gradual Change

The application of GIS in forest has thoroughly changed the way to manage forest reserves (forest reserves and GIS has become a new tool of modern forest management. However, along with the use in a deep going way, most users find that the forest reserves map which is built by traditional vector data models in GIS is different from the real.: In traditional forest distribution map, we give tacit consent to the fact that the forest is represented by a polygon, whose boundary is taken as a abrupt change between different types and the interior of the polygon is regarded as uniform. But in the real world, the transition region of forest from one type to another is a evident gradual change. This loss of information may result in error decision for forest management, such as the forecast of forest fire and formulation of forest-fell plan.The abrupt change and gradual change coexist in forest distribution. In order to represent forest distribution more precisely, in this paper we propose a new data model which can both represent the abrupt change and gradual change of forest distribution based on the character of forest distribution.By using the experience of the merit of field-based data models, this paper divides the forest space into abrupt lines, equal regions, and gradual regions and put forward feature-point-set to represent gradual regions. Then we design the data model's architecture and primary classes using object-oriented method.At last, on the basis of design model's characters and the implementation of representation in gradual zones, figure display and attribute query by feature-point-set, this paper develops a program to validate the possibility and correctness of the design model .Finally it concludes that the design model can realize the goal of representing the abrupt and gradual change of the forest space concurrently.