Function IsoPoly2DynFast(filename: string; link: integer; percent: double; Doughnut: boolean; buffer: double): integer;
This is the same function as IsoPoly2Dyn, except the required bounding box gets calculated for the user with a buffer added. We recommend a value of 3 km / 2 miles in urban areas and more in rural areas (>10).
This means the calculation goes much faster for small isochrones in large networks and the RAM requirement is also greatly reduced.
There is a small risk of not getting the exact same result as calling IsoPoly2Dyn with 0,0,0,0 as parameter, but this should only occur in extreme situations.