IsoPoly2Fast

Function IsoPoly2Fast(filename: string; nodenum: integer; Doughnut: boolean; buffer: double): integer;

This is the same function as IsoPoly2, 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 IsoPoly2 with 0,0,0,0 as parameter, but this should only occur in extreme situations. If so, increase the size of the buffer.