Intersection
IntersectionGenerator::GetActualNextIntersection(const NodeID starting_node,
const EdgeID via_edge,
NodeID *resulting_from_node = nullptr,
EdgeID *resulting_via_edge = nullptr) const
{
// This function skips over traffic lights/graph compression issues and similar to find the next
// actual intersection
Intersection result = GetConnectedRoads(starting_node, via_edge);
// Skip over stuff that has not been compressed due to barriers/parallel edges
NodeID node_at_intersection = starting_node;
EdgeID incoming_edge = via_edge;
// to prevent endless loops
const auto termination_node = node_based_graph.GetTarget(via_edge);
// using a maximum lookahead, we make sure not to end up in some form of loop
std::unordered_set<NodeID> visited_nodes;
while (visited_nodes.count(node_at_intersection) == 0 &&
(result.size() == 2 &&
node_based_graph.GetEdgeData(via_edge).IsCompatibleTo(
node_based_graph.GetEdgeData(result[1].eid))))
{
visited_nodes.insert(node_at_intersection);
node_at_intersection = node_based_graph.GetTarget(incoming_edge);
incoming_edge = result[1].eid;
result = GetConnectedRoads(node_at_intersection, incoming_edge);
// When looping back to the original node, we obviously are in a loop. Stop there.
if (termination_node == node_based_graph.GetTarget(incoming_edge))
break;
}
// return output if requested
if (resulting_from_node)
*resulting_from_node = node_at_intersection;
if (resulting_via_edge)
*resulting_via_edge = incoming_edge;
return result;
}
/*
* Segregated Roads often merge onto a single intersection.
* While technically representing different roads, they are
* often looked at as a single road.
* Due to the merging, turn Angles seem off, wenn we compute them from the
* initial positions.
*
* b<b<b<b(1)<b<b<b
* aaaaa-b
* b>b>b>b(2)>b>b>b
*
* Would be seen as a slight turn going fro a to (2). A Sharp turn going from
* (1) to (2).
*
* In cases like these, we megre this segregated roads into a single road to
* end up with a case like:
*
* aaaaa-bbbbbb
*
* for the turn representation.
* Anything containing the first u-turn in a merge affects all other angles
* and is handled separately from all others.
*/
Intersection IntersectionGenerator::mergeSegregatedRoads(Intersection intersection) const
{
const auto getRight = [&](std::size_t index) {
return (index + intersection.size() - 1) % intersection.size();
};
const auto mergable = [&](std::size_t first, std::size_t second) -> bool {
const auto &first_data = node_based_graph.GetEdgeData(intersection[first].turn.eid);
const auto &second_data = node_based_graph.GetEdgeData(intersection[second].turn.eid);
return first_data.name_id != INVALID_NAME_ID && first_data.name_id == second_data.name_id &&
!first_data.roundabout && !second_data.roundabout &&
first_data.travel_mode == second_data.travel_mode &&
first_data.road_classification == second_data.road_classification &&
// compatible threshold
angularDeviation(intersection[first].turn.angle, intersection[second].turn.angle) <
60 &&
first_data.reversed != second_data.reversed;
};
const auto merge = [](const ConnectedRoad &first,
const ConnectedRoad &second) -> ConnectedRoad {
if (!first.entry_allowed)
{
ConnectedRoad result = second;
result.turn.angle = (first.turn.angle + second.turn.angle) / 2;
if (first.turn.angle - second.turn.angle > 180)
result.turn.angle += 180;
if (result.turn.angle > 360)
result.turn.angle -= 360;
return result;
}
else
{
BOOST_ASSERT(!second.entry_allowed);
ConnectedRoad result = first;
result.turn.angle = (first.turn.angle + second.turn.angle) / 2;
if (first.turn.angle - second.turn.angle > 180)
result.turn.angle += 180;
if (result.turn.angle > 360)
result.turn.angle -= 360;
return result;
}
};
if (intersection.size() <= 1)
return intersection;
const bool is_connected_to_roundabout = [this, &intersection]() {
for (const auto &road : intersection)
{
if (node_based_graph.GetEdgeData(road.turn.eid).roundabout)
return true;
}
return false;
}();
// check for merges including the basic u-turn
// these result in an adjustment of all other angles
if (mergable(0, intersection.size() - 1))
{
const double correction_factor =
(360 - intersection[intersection.size() - 1].turn.angle) / 2;
for (std::size_t i = 1; i + 1 < intersection.size(); ++i)
intersection[i].turn.angle += correction_factor;
// FIXME if we have a left-sided country, we need to switch this off and enable it below
intersection[0] = merge(intersection.front(), intersection.back());
intersection[0].turn.angle = 0;
if (is_connected_to_roundabout)
{
// We are merging a u-turn against the direction of a roundabout
//
// -----------> roundabout
// / \
// out in
//
// These cases have to be disabled, even if they are not forbidden specifically by a
// relation
intersection[0].entry_allowed = false;
}
intersection.pop_back();
}
else if (mergable(0, 1))
{
const double correction_factor = (intersection[1].turn.angle) / 2;
for (std::size_t i = 2; i < intersection.size(); ++i)
intersection[i].turn.angle += correction_factor;
intersection[0] = merge(intersection[0], intersection[1]);
intersection[0].turn.angle = 0;
intersection.erase(intersection.begin() + 1);
}
// a merge including the first u-turn requres an adjustment of the turn angles
// therefore these are handled prior to this step
for (std::size_t index = 2; index < intersection.size(); ++index)
{
if (mergable(index, getRight(index)))
{
intersection[getRight(index)] =
merge(intersection[getRight(index)], intersection[index]);
intersection.erase(intersection.begin() + index);
--index;
}
}
const auto ByAngle = [](const ConnectedRoad &first, const ConnectedRoad second) {
return first.turn.angle < second.turn.angle;
};
std::sort(std::begin(intersection), std::end(intersection), ByAngle);
return intersection;
}
std::pair<util::guidance::EntryClass, util::guidance::BearingClass>
classifyIntersection(Intersection intersection)
{
if (intersection.empty())
return {};
std::sort(intersection.begin(),
intersection.end(),
[](const ConnectedRoad &left, const ConnectedRoad &right) {
return left.bearing < right.bearing;
});
util::guidance::EntryClass entry_class;
util::guidance::BearingClass bearing_class;
const bool canBeDiscretized = [&]() {
if (intersection.size() <= 1)
return true;
DiscreteBearing last_discrete_bearing = util::guidance::BearingClass::getDiscreteBearing(
std::round(intersection.back().bearing));
for (const auto road : intersection)
{
const DiscreteBearing discrete_bearing =
util::guidance::BearingClass::getDiscreteBearing(std::round(road.bearing));
if (discrete_bearing == last_discrete_bearing)
return false;
last_discrete_bearing = discrete_bearing;
}
return true;
}();
// finally transfer data to the entry/bearing classes
std::size_t number = 0;
if (canBeDiscretized)
{
if (util::guidance::BearingClass::getDiscreteBearing(intersection.back().bearing) <
util::guidance::BearingClass::getDiscreteBearing(intersection.front().bearing))
{
intersection.insert(intersection.begin(), intersection.back());
intersection.pop_back();
}
for (const auto &road : intersection)
{
if (road.entry_allowed)
entry_class.activate(number);
auto discrete_bearing_class =
util::guidance::BearingClass::getDiscreteBearing(std::round(road.bearing));
bearing_class.add(std::round(discrete_bearing_class *
util::guidance::BearingClass::discrete_step_size));
++number;
}
}
else
{
for (const auto &road : intersection)
{
if (road.entry_allowed)
entry_class.activate(number);
bearing_class.add(std::round(road.bearing));
++number;
}
}
return std::make_pair(entry_class, bearing_class);
}
// a
// |
// |
// v
// For an intersection from_node --via_edi--> turn_node ----> c
// ^
// |
// |
// b
// This functions returns _all_ turns as if the graph was undirected.
// That means we not only get (from_node, turn_node, c) in the above example
// but also (from_node, turn_node, a), (from_node, turn_node, b). These turns are
// marked as invalid and only needed for intersection classification.
Intersection IntersectionGenerator::GetConnectedRoads(const NodeID from_node,
const EdgeID via_eid) const
{
Intersection intersection;
const NodeID turn_node = node_based_graph.GetTarget(via_eid);
// reserve enough items (+ the possibly missing u-turn edge)
intersection.reserve(node_based_graph.GetOutDegree(turn_node) + 1);
const NodeID only_restriction_to_node = [&]() {
// If only restrictions refer to invalid ways somewhere far away, we rather ignore the
// restriction than to not route over the intersection at all.
const auto only_restriction_to_node =
restriction_map.CheckForEmanatingIsOnlyTurn(from_node, turn_node);
if (only_restriction_to_node != SPECIAL_NODEID)
{
// check if we can find an edge in the edge-rage
for (const auto onto_edge : node_based_graph.GetAdjacentEdgeRange(turn_node))
if (only_restriction_to_node == node_based_graph.GetTarget(onto_edge))
return only_restriction_to_node;
}
// Ignore broken only restrictions.
return SPECIAL_NODEID;
}();
const bool is_barrier_node = barrier_nodes.find(turn_node) != barrier_nodes.end();
bool has_uturn_edge = false;
bool uturn_could_be_valid = false;
const util::Coordinate turn_coordinate = node_info_list[turn_node];
const auto intersection_lanes = getLaneCountAtIntersection(turn_node, node_based_graph);
for (const EdgeID onto_edge : node_based_graph.GetAdjacentEdgeRange(turn_node))
{
BOOST_ASSERT(onto_edge != SPECIAL_EDGEID);
const NodeID to_node = node_based_graph.GetTarget(onto_edge);
const auto &onto_data = node_based_graph.GetEdgeData(onto_edge);
bool turn_is_valid =
// reverse edges are never valid turns because the resulting turn would look like this:
// from_node --via_edge--> turn_node <--onto_edge-- to_node
// however we need this for capture intersection shape for incoming one-ways
!onto_data.reversed &&
// we are not turning over a barrier
(!is_barrier_node || from_node == to_node) &&
// We are at an only_-restriction but not at the right turn.
(only_restriction_to_node == SPECIAL_NODEID || to_node == only_restriction_to_node) &&
// the turn is not restricted
!restriction_map.CheckIfTurnIsRestricted(from_node, turn_node, to_node);
auto angle = 0.;
double bearing = 0.;
// The first coordinate (the origin) can depend on the number of lanes turning onto,
// just as the target coordinate can. Here we compute the corrected coordinate for the
// incoming edge.
const auto first_coordinate = coordinate_extractor.GetCoordinateAlongRoad(
from_node, via_eid, INVERT, turn_node, intersection_lanes);
if (from_node == to_node)
{
bearing = util::coordinate_calculation::bearing(turn_coordinate, first_coordinate);
uturn_could_be_valid = turn_is_valid;
if (turn_is_valid && !is_barrier_node)
{
// we only add u-turns for dead-end streets.
if (node_based_graph.GetOutDegree(turn_node) > 1)
{
auto number_of_emmiting_bidirectional_edges = 0;
for (auto edge : node_based_graph.GetAdjacentEdgeRange(turn_node))
{
auto target = node_based_graph.GetTarget(edge);
auto reverse_edge = node_based_graph.FindEdge(target, turn_node);
BOOST_ASSERT(reverse_edge != SPECIAL_EDGEID);
if (!node_based_graph.GetEdgeData(reverse_edge).reversed)
{
++number_of_emmiting_bidirectional_edges;
}
}
// is a dead-end, only possible road is to go back
turn_is_valid = number_of_emmiting_bidirectional_edges <= 1;
}
}
has_uturn_edge = true;
BOOST_ASSERT(angle >= 0. && angle < std::numeric_limits<double>::epsilon());
}
else
{
// the default distance we lookahead on a road. This distance prevents small mapping
// errors to impact the turn angles.
const auto third_coordinate = coordinate_extractor.GetCoordinateAlongRoad(
turn_node, onto_edge, !INVERT, to_node, intersection_lanes);
angle = util::coordinate_calculation::computeAngle(
first_coordinate, turn_coordinate, third_coordinate);
bearing = util::coordinate_calculation::bearing(turn_coordinate, third_coordinate);
if (std::abs(angle) < std::numeric_limits<double>::epsilon())
has_uturn_edge = true;
}
intersection.push_back(
ConnectedRoad(TurnOperation{onto_edge,
angle,
bearing,
{TurnType::Invalid, DirectionModifier::UTurn},
INVALID_LANE_DATAID},
turn_is_valid));
}
// We hit the case of a street leading into nothing-ness. Since the code here assumes
// that this
// will never happen we add an artificial invalid uturn in this case.
if (!has_uturn_edge)
{
const auto first_coordinate = coordinate_extractor.GetCoordinateAlongRoad(
from_node,
via_eid,
INVERT,
turn_node,
node_based_graph.GetEdgeData(via_eid).road_classification.GetNumberOfLanes());
const double bearing =
util::coordinate_calculation::bearing(turn_coordinate, first_coordinate);
intersection.push_back({TurnOperation{via_eid,
0.,
bearing,
{TurnType::Invalid, DirectionModifier::UTurn},
INVALID_LANE_DATAID},
false});
}
std::sort(std::begin(intersection),
std::end(intersection),
std::mem_fn(&ConnectedRoad::compareByAngle));
BOOST_ASSERT(intersection[0].angle >= 0. &&
intersection[0].angle < std::numeric_limits<double>::epsilon());
const auto valid_count =
boost::count_if(intersection, [](const ConnectedRoad &road) { return road.entry_allowed; });
if (0 == valid_count && uturn_could_be_valid)
{
// after intersections sorting by angles, find the u-turn with (from_node ==
// to_node)
// that was inserted together with setting uturn_could_be_valid flag
std::size_t self_u_turn = 0;
while (self_u_turn < intersection.size() &&
intersection[self_u_turn].angle < std::numeric_limits<double>::epsilon() &&
from_node != node_based_graph.GetTarget(intersection[self_u_turn].eid))
{
++self_u_turn;
}
BOOST_ASSERT(from_node == node_based_graph.GetTarget(intersection[self_u_turn].eid));
intersection[self_u_turn].entry_allowed = true;
}
return intersection;
}
