Figure 21
From: Gravity law in the Chinese highway freight transportation networks
![Figure 21](http://media.springernature.com/full/springer-static/image/art%3A10.1140%2Fepjds%2Fs13688-019-0216-6/MediaObjects/13688_2019_216_Fig21_HTML.jpg)
Evolution of the exponents of daily directed and undirected freight highway transportation networks. (a) Scatter data of \(F_{ij}\) with respect to \((G_{i}/P_{i})^{\alpha_{1}}(G_{j}/P_{j})^{\alpha_{2}}/d_{ij}^{\alpha _{3}}\) for the directed network. (b) Binning data of \(F_{ij}\) with respect to \((G_{i}/P_{i})^{\alpha_{1}}(G_{j}/P_{j})^{\alpha_{2}}/d_{ij}^{\alpha_{3}}\) for the directed network. (c) Scatter data of \(W_{ij}\) with respect to \((G_{i}/P_{i})^{\alpha_{1}}(G_{j}/P_{j})^{\alpha_{2}}/d_{ij}^{\alpha_{3}}\) for the undirected network. (d) Binning data of \(W_{ij}\) with respect to \((G_{i}/P_{i})^{\alpha_{1}}(G_{j}/P_{j})^{\alpha_{2}}/d_{ij}^{\alpha_{3}}\) for the undirected network