Visualising vector fields

The above methods are all well applicable to scalar data, but fail to display vector fields. It is possible, and sometimes useful to display only the magnitude of the vectors, but that gives no idea about the direction of the flow or the path of material transport. One approach would be to colour code directions, but reading that needs an experienced eye, and in most cases we have to trade in the display of the magnitude in exchange. The solution here is the same as before, we have to select a set of points that represent the entire flow.