// 2. Compute the set of initial points
long t1 = System.currentTimeMillis();
List<Coordinate> initialPoints = computeInitialPoints(spt);
// 3. Compute the isochrone based on the SPT.
ZFunc timeFunc = new ZFunc() {
@Override
public long z(Coordinate c) {
// TODO Make the sample source multi-router compatible
Sample sample = sampleSource.getSample(c.x, c.y);
if (sample == null) {