float rot = track.get_rotation();
string transform = format("translate(%.3f %.3f) rotate(%.3f)", pos.x*1000, -pos.y*1000, -rot*180/M_PI);
group.set_attribute("transform", transform);
float rot = track.get_rotation();
string transform = format("translate(%.3f %.3f) rotate(%.3f)", pos.x*1000, -pos.y*1000, -rot*180/M_PI);
group.set_attribute("transform", transform);