Impact computations in the general spatial interaction model

We extend the impact decomposition proposed by LeSage and Thomas-Agnan (2015) in the spatialinteraction model to a more general framework, where the sets of origins and destinations can bedifferent, and where the relevant attributes characterizing the origins do not coincide with those of thedestinations. These extensions result in three flow data configurations which we study extensively: thesquare, the rectangular, and the non-cartesian cases. We propose numerical simplifications to computethe impacts, avoiding the inversion of a large filter matrix. These simplifications considerably reducecomputation time; they can also be useful for prediction. Furthermore, we define local measuresfor the intra, origin, destination and network effects. Interestingly, these local measures can beaggregated at different levels of analysis. Finally, we illustrate our methodology in a case study usingremittance flows all over the world