The implementation and visualization of a large spatial individual-based model using Fortran 90

We look in detail at the implementation of a simulation of the spread of Barley Yellow Dwarf Virus in a barley eld. The model considers explicitly each individual plant and aphid, therefore it requires special care to reduce the amount of storage used whilst still producing a computationally ecient code. We attempt to quantify the cost of some of the decisions made in terms of their memory and processor time requirements. Finally we briey consider the visualisation of the results and how the amount of data produced by the model may be reduced to a manageable level.