文章编号：1672-5328（2009）02-0074-07

陈仁春
（福州市城市规划设计研究院，福建 福州 350003）

摘要：双约束重力模型对多中心、长距离组团之间的出行分布描述误差较大，因此需要建立一种多条件的约束模型。从最大熵模型理论入手，在产生量与吸引量双约束基础上，新增第3类约束条件。利用总体阻抗约束最大熵模型推导出三维约束重力模型的一般形式，增加了缩放系数，并利用重力式先验概率的最大熵模型对其进行论证。同时，提出了模型参数标定与检验方法。以福州市交通分布模型为例，对长距离出行约束和跨江出行约束进行分析，并分别应用双约束和三维约束重力模型进行计算，结果说明了三维约束重力模型的可操作性和优越性。

关键词：交通规划；交通模型；三维约束重力模型；缩放系数；参数标定

中图分类号：U491.1⁺2

文献标识码：A

Tri-constrained Gravity Model and its Application

CHEN Ren-chun
(Fuzhou Planning Design & Research Institute, Fuzhou Fujian 350003, China)

Abstract：The double-constrained gravity model may generate relatively large errors of trip distributions among distantly separated land-use groups of multi-centers. Therefore, there is need to develop a new constrained model under more conditions. In light of the maximum entropy theory, and considering a third constrain in addition to the double constrains of Os and Ds, this paper formulates a general equation of a tri-constrained gravity model by introducing the total impedance entropy-maximizing model with a relaxing factor, and further performs a verification through the priori-probability of the gravity entropy-maximizing model. Meanwhile, the paper presents a methodology to calibrate and validate the model. The paper also reports a demonstrative application in the City of Fuzhou, Fujian Province, with the constrains of long distance trips and cross-river trips tested using the double-constrained and the tri-constrained gravity models, respectively. The results show that the tri-constrained gravity model is more promising in real-world implementation.

Keywords：transportation planning; transportation model; tri-constrained gravity model; relaxing factor; parameters calibration