default:
EastNorth P = n.getEastNorth();
seg = segs.iterator().next();
A = seg.a.getEastNorth();
B = seg.b.getEastNorth();
double a = P.distanceSq(B);
double b = P.distanceSq(A);
double c = A.distanceSq(B);
q = (a - b + c) / (2*c);
n.setEastNorth(new EastNorth(B.east() + q * (A.east() - B.east()), B.north() + q * (A.north() - B.north())));
}