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Construct adjacency list and properly traverse it.

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This commit is contained in:
Daniel Patterson 2016-11-04 23:35:42 -06:00
parent d21c8e3800
commit f96e61ee06
2 changed files with 182 additions and 218 deletions
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398
src/engine/plugins/tile.cpp
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@ -387,259 +387,218 @@ Status TilePlugin::HandleRequest(const std::shared_ptr<datafacade::BaseDataFacad
// are all pointed in the same direction.
struct EdgeBasedNodeInfo
{
unsigned source_intersection; // node-based-node ID
unsigned target_intersection; // node-based-node ID
bool is_geometry_forward; // Is the geometry forward or reverse?
bool is_geometry_forward; // Is the geometry forward or reverse?
unsigned packed_geometry_id;
};
// Lookup table for edge-based-nodes
std::unordered_map<NodeID, EdgeBasedNodeInfo> edge_based_node_info;
std::unordered_map<NodeID, std::vector<EdgeID>> outgoing_edges;
std::unordered_map<NodeID, std::vector<EdgeID>> incoming_edges;
// Now, loop over all the road segments we saw, and build up a mini
// graph for just the network that's visible.
struct SegmentData
{
NodeID target_node;
EdgeID edge_based_node_id;
};
std::unordered_map<NodeID, std::vector<SegmentData>> directed_graph;
// Build an adjacency list for all the road segments visible in
// the tile
for (const auto &edge : edges)
{
// Note: edge.u is the node-based node ID of the source intersection
// edge.v is the node-based node ID of the target intersection
// both these values can be directly looked up for coordinates
// If forward travel is enabled on this road section, and we haven't seen this
// edge-based-node
// before
if (edge.forward_segment_id.enabled &&
edge_based_node_info.count(edge.forward_segment_id.id) == 0)
if (edge.forward_segment_id.enabled)
{
// Add this edge-based-nodeid as an outgoing from the source intersection
const auto outgoing_itr_u = outgoing_edges.find(edge.u);
if (outgoing_itr_u != outgoing_edges.end())
if (directed_graph.count(edge.u) == 0)
{
outgoing_itr_u->second.push_back(edge.forward_segment_id.id);
directed_graph[edge.u] = {{edge.v, edge.forward_segment_id.id}};
}
else
{
outgoing_edges[edge.u] = {edge.forward_segment_id.id};
directed_graph[edge.u].push_back({edge.v, edge.forward_segment_id.id});
}
// Add this edge-based-nodeid as an incoming to the target intersection
const auto incoming_itr_v = incoming_edges.find(edge.v);
if (incoming_itr_v != incoming_edges.end())
{
incoming_itr_v->second.push_back(edge.forward_segment_id.id);
}
else
{
incoming_edges[edge.v] = {edge.forward_segment_id.id};
}
edge_based_node_info[edge.forward_segment_id.id] = {
edge.u, edge.v, true, edge.packed_geometry_id};
edge_based_node_info[edge.forward_segment_id.id] = {true, edge.packed_geometry_id};
}
// Same as previous block, but everything flipped
if (edge.reverse_segment_id.enabled &&
edge_based_node_info.count(edge.reverse_segment_id.id) == 0)
if (edge.reverse_segment_id.enabled)
{
auto f = outgoing_edges.find(edge.v);
if (f != outgoing_edges.end())
if (directed_graph.count(edge.v) == 0)
{
f->second.push_back(edge.reverse_segment_id.id);
directed_graph[edge.v] = {{edge.u, edge.reverse_segment_id.id}};
}
else
{
outgoing_edges[edge.v] = {edge.reverse_segment_id.id};
directed_graph[edge.v].push_back({edge.u, edge.reverse_segment_id.id});
}
f = incoming_edges.find(edge.u);
if (f != incoming_edges.end())
{
f->second.push_back(edge.reverse_segment_id.id);
}
else
{
incoming_edges[edge.u] = {edge.reverse_segment_id.id};
}
// Save info about this edge-based-node, note reversal from forward
// block above.
edge_based_node_info[edge.reverse_segment_id.id] = {
edge.v, edge.u, false, edge.packed_geometry_id};
edge_based_node_info[edge.reverse_segment_id.id] = {false, edge.packed_geometry_id};
}
}
// Now, for every edge-based-node that we discovered (edge-based-nodes are sources
// and targets of turns). EBN is short for edge-based-node
std::vector<NodeID> first_geometry, second_geometry;
// Now, scan over our adjacency list
// For every edge A:
// Look at the outgoing edges from A
// If the outgoing edge has a different edge_based_node_id
// This is a turn. Find it in the CH
// Get the edge data
// Subtract the road weights from the edge weight
// Calculate angles, add to tile.
std::vector<contractor::QueryEdge::EdgeData> unpacked_shortcut;
std::vector<EdgeWeight> first_weight_vector;
for (const auto &source_ebn : edge_based_node_info)
for (const auto &firstnode : directed_graph)
{
if (outgoing_edges.count(source_ebn.second.target_intersection) == 0)
for (const auto &firstedge : firstnode.second)
{
continue;
}
// Grab a copy of the geometry leading up to the intersection.
if (source_ebn.second.is_geometry_forward)
{
first_geometry =
facade->GetUncompressedForwardGeometry(source_ebn.second.packed_geometry_id);
}
else
{
first_geometry =
facade->GetUncompressedReverseGeometry(source_ebn.second.packed_geometry_id);
}
// We earlier saved the source and target intersection nodes for every road section.
// We can use the target node to find all road sections that lead away from
// the intersection, and thus
// in the graph after our main
for (const auto &target_ebn : outgoing_edges[source_ebn.second.target_intersection])
{
// Ignore u-turns for now
if (edge_based_node_info.at(target_ebn).target_intersection ==
source_ebn.second.source_intersection)
// If this edge points to something else (i.e. degree > 1)
if (directed_graph.count(firstedge.target_node) > 0)
{
continue;
}
// For each of the outgoing edges from our target coordinate
for (const auto &secondedge : directed_graph[firstedge.target_node])
{
// If the next edge has the same edge_based_node_id, then it's
// not a turn, so skip it
if (firstedge.edge_based_node_id == secondedge.edge_based_node_id)
continue;
// Find the connection between our source road and the target node
EdgeID smaller_edge_id = facade->FindSmallestEdge(
source_ebn.first, target_ebn, [](const contractor::QueryEdge::EdgeData &data) {
return data.forward;
});
// Skip u-turns
if (firstnode.first == secondedge.target_node)
continue;
// Depending on how the graph is constructed, we might have to look for
// a backwards edge instead. They're equivalent, just one is available for
// a forward routing search, and one is used for the backwards dijkstra
// steps. Their weight should be the same, we can use either one.
// If we didn't find a forward edge, try for a backward one
if (SPECIAL_EDGEID == smaller_edge_id)
{
smaller_edge_id = facade->FindSmallestEdge(
target_ebn,
source_ebn.first,
[](const contractor::QueryEdge::EdgeData &data) { return data.backward; });
}
// Find the connection between our source road and the target node
EdgeID smaller_edge_id = facade->FindSmallestEdge(
firstedge.edge_based_node_id,
secondedge.edge_based_node_id,
[](const contractor::QueryEdge::EdgeData &data) {
return data.forward;
});
// If no edge was found, it means that there's no connection between these nodes,
// due to oneways or turn restrictions. Given the edge-based-nodes that
// we're examining here, we *should* only find directly-connected edges, not
// shortcuts
if (smaller_edge_id != SPECIAL_EDGEID)
{
// Check to see if it was a shortcut edge we found. This can happen
// when exactly? Anyway, unpack it and get the first "real" edgedata
// out of it, which should represent the first hop, which is the one
// we want to find the turn.
const auto &data = [this,
&facade,
smaller_edge_id,
source_ebn,
target_ebn,
&unpacked_shortcut]() {
const auto inner_data = facade->GetEdgeData(smaller_edge_id);
if (inner_data.shortcut)
// Depending on how the graph is constructed, we might have to look for
// a backwards edge instead. They're equivalent, just one is available for
// a forward routing search, and one is used for the backwards dijkstra
// steps. Their weight should be the same, we can use either one.
// If we didn't find a forward edge, try for a backward one
if (SPECIAL_EDGEID == smaller_edge_id)
{
unpacked_shortcut.clear();
UnpackEdgeToEdges(
*facade, source_ebn.first, target_ebn, unpacked_shortcut);
return unpacked_shortcut.front();
smaller_edge_id = facade->FindSmallestEdge(
secondedge.edge_based_node_id,
firstedge.edge_based_node_id,
[](const contractor::QueryEdge::EdgeData &data) {
return data.backward;
});
}
else
return inner_data;
}();
BOOST_ASSERT_MSG(!data.shortcut, "Connecting edge must not be a shortcut");
// This is the geometry leading away from the intersection
// (i.e. the forward geometry of the target edge-based-node)
// If no edge was found, it means that there's no connection between these
// nodes, due to oneways or turn restrictions. Given the edge-based-nodes
// that we're examining here, we *should* only find directly-connected
// edges, not shortcuts
if (smaller_edge_id != SPECIAL_EDGEID)
{
// Check to see if it was a shortcut edge we found. This can happen
// when exactly? Anyway, unpack it and get the first "real" edgedata
// out of it, which should represent the first hop, which is the one
// we want to find the turn.
const auto &data = [this,
&facade,
smaller_edge_id,
firstedge,
secondedge,
&unpacked_shortcut]() {
const auto inner_data = facade->GetEdgeData(smaller_edge_id);
if (inner_data.shortcut)
{
unpacked_shortcut.clear();
UnpackEdgeToEdges(*facade,
firstedge.edge_based_node_id,
secondedge.edge_based_node_id,
unpacked_shortcut);
return unpacked_shortcut.front();
}
else
return inner_data;
}();
BOOST_ASSERT_MSG(!data.shortcut,
"Connecting edge must not be a shortcut");
if (!edge_based_node_info.at(target_ebn).is_geometry_forward)
{
second_geometry = facade->GetUncompressedForwardGeometry(
edge_based_node_info.at(target_ebn).packed_geometry_id);
// Now, calculate the sum of the weight of all the segments.
if (edge_based_node_info[firstedge.edge_based_node_id]
.is_geometry_forward)
{
first_weight_vector = facade->GetUncompressedForwardWeights(
edge_based_node_info[firstedge.edge_based_node_id]
.packed_geometry_id);
}
else
{
first_weight_vector = facade->GetUncompressedReverseWeights(
edge_based_node_info[firstedge.edge_based_node_id]
.packed_geometry_id);
}
const auto sum_node_weight =
std::accumulate(first_weight_vector.begin(),
first_weight_vector.end(),
EdgeWeight{0});
// The edge.weight is the whole edge weight, which includes the turn
// cost.
// The turn cost is the edge.weight minus the sum of the individual road
// segment weights. This might not be 100% accurate, because some
// intersections include stop signs, traffic signals and other
// penalties, but at this stage, we can't divide those out, so we just
// treat the whole lot as the "turn cost" that we'll stick on the map.
const auto turn_cost = data.weight - sum_node_weight;
// Find the three nodes that make up the turn movement)
const auto node_from = firstnode.first;
const auto node_via = firstedge.target_node;
const auto node_to = secondedge.target_node;
const auto coord_from = facade->GetCoordinateOfNode(node_from);
const auto coord_via = facade->GetCoordinateOfNode(node_via);
const auto coord_to = facade->GetCoordinateOfNode(node_to);
// Calculate the bearing that we approach the intersection at
const auto angle_in = static_cast<int>(
util::coordinate_calculation::bearing(coord_from, coord_via));
// Add the angle to the values table for the vector tile, and get the
// index
// of that value in the table
const auto angle_in_index = use_point_int_value(angle_in);
// Calculate the bearing leading away from the intersection
const auto exit_bearing = static_cast<int>(
util::coordinate_calculation::bearing(coord_via, coord_to));
// Figure out the angle of the turn
auto turn_angle = exit_bearing - angle_in;
while (turn_angle > 180)
{
turn_angle -= 360;
}
while (turn_angle < -180)
{
turn_angle += 360;
}
// Add the turn angle value to the value lookup table for the vector
// tile.
const auto turn_angle_index = use_point_int_value(turn_angle);
// And, same for the actual turn cost value - it goes in the lookup
// table,
// not directly on the feature itself.
const auto turn_cost_index = use_point_float_value(
turn_cost / 10.0); // Note conversion to float here
// Save everything we need to later add all the points to the tile.
// We need the coordinate of the intersection, the angle in, the turn
// angle and the turn cost.
all_turn_data.emplace_back(TurnData{
coord_via, angle_in_index, turn_angle_index, turn_cost_index});
}
}
else
{
second_geometry = facade->GetUncompressedReverseGeometry(
edge_based_node_info.at(target_ebn).packed_geometry_id);
}
// Now, calculate the sum of the weight of all the segments.
if (source_ebn.second.is_geometry_forward)
{
first_weight_vector = facade->GetUncompressedForwardWeights(
source_ebn.second.packed_geometry_id);
}
else
{
first_weight_vector = facade->GetUncompressedReverseWeights(
source_ebn.second.packed_geometry_id);
}
const auto sum_node_weight = std::accumulate(
first_weight_vector.begin(), first_weight_vector.end(), EdgeWeight{0});
// The edge.weight is the whole edge weight, which includes the turn cost.
// The turn cost is the edge.weight minus the sum of the individual road
// segment weights. This might not be 100% accurate, because some
// intersections include stop signs, traffic signals and other penalties,
// but at this stage, we can't divide those out, so we just treat the whole
// lot as the "turn cost" that we'll stick on the map.
const auto turn_cost = data.weight - sum_node_weight;
// Find the three nodes that make up the turn movement)
const auto node_from = first_geometry.size() > 1
? *(first_geometry.end() - 2)
: source_ebn.second.source_intersection;
const auto node_via = source_ebn.second.target_intersection;
const auto node_to = second_geometry.front();
const auto coord_from = facade->GetCoordinateOfNode(node_from);
const auto coord_via = facade->GetCoordinateOfNode(node_via);
const auto coord_to = facade->GetCoordinateOfNode(node_to);
// Calculate the bearing that we approach the intersection at
const auto angle_in = static_cast<int>(
util::coordinate_calculation::bearing(coord_from, coord_via));
// Add the angle to the values table for the vector tile, and get the index
// of that value in the table
const auto angle_in_index = use_point_int_value(angle_in);
// Calculate the bearing leading away from the intersection
const auto exit_bearing = static_cast<int>(
util::coordinate_calculation::bearing(coord_via, coord_to));
// Figure out the angle of the turn
auto turn_angle = exit_bearing - angle_in;
while (turn_angle > 180)
{
turn_angle -= 360;
}
while (turn_angle < -180)
{
turn_angle += 360;
}
// Add the turn angle value to the value lookup table for the vector tile.
const auto turn_angle_index = use_point_int_value(turn_angle);
// And, same for the actual turn cost value - it goes in the lookup table,
// not directly on the feature itself.
const auto turn_cost_index =
use_point_float_value(turn_cost / 10.0); // Note conversion to float here
// Save everything we need to later add all the points to the tile.
// We need the coordinate of the intersection, the angle in, the turn
// angle and the turn cost.
all_turn_data.emplace_back(
TurnData{coord_via, angle_in_index, turn_angle_index, turn_cost_index});
}
}
}
}
// Vector tiles encode feature properties as indexes into a lookup table. So, we need to
// Vector tiles encode feature properties as indexes into a lookup table. So, we need
// to
// "pre-loop" over all the edges to create the lookup tables. Once we have those, we
// can then encode the features, and we'll know the indexes that feature properties
// need to refer to.
@ -679,7 +638,8 @@ Status TilePlugin::HandleRequest(const std::shared_ptr<datafacade::BaseDataFacad
protozero::pbf_writer tile_writer{pbf_buffer};
{
{
// Add a layer object to the PBF stream. 3=='layer' from the vector tile spec (2.1)
// Add a layer object to the PBF stream. 3=='layer' from the vector tile spec
// (2.1)
protozero::pbf_writer line_layer_writer(tile_writer, util::vector_tile::LAYER_TAG);
// TODO: don't write a layer if there are no features
@ -749,8 +709,10 @@ Status TilePlugin::HandleRequest(const std::shared_ptr<datafacade::BaseDataFacad
const std::size_t name_idx,
std::int32_t &start_x,
std::int32_t &start_y) {
// Here, we save the two attributes for our feature: the speed and the
// is_small boolean. We only serve up speeds from 0-139, so all we do is
// Here, we save the two attributes for our feature: the speed and
// the
// is_small boolean. We only serve up speeds from 0-139, so all we
// do is
// save the first
protozero::pbf_writer feature_writer(line_layer_writer,
util::vector_tile::FEATURE_TAG);
@ -846,7 +808,8 @@ Status TilePlugin::HandleRequest(const std::shared_ptr<datafacade::BaseDataFacad
}
// Field id 3 is the "keys" attribute
// We need two "key" fields, these are referred to with 0 and 1 (their array indexes)
// We need two "key" fields, these are referred to with 0 and 1 (their array
// indexes)
// earlier
line_layer_writer.add_string(util::vector_tile::KEY_TAG, "speed");
line_layer_writer.add_string(util::vector_tile::KEY_TAG, "is_small");
@ -912,7 +875,8 @@ Status TilePlugin::HandleRequest(const std::shared_ptr<datafacade::BaseDataFacad
if (!all_turn_data.empty())
{
// Now write the points layer for turn penalty data:
// Add a layer object to the PBF stream. 3=='layer' from the vector tile spec (2.1)
// Add a layer object to the PBF stream. 3=='layer' from the vector tile spec
// (2.1)
protozero::pbf_writer point_layer_writer(tile_writer, util::vector_tile::LAYER_TAG);
point_layer_writer.add_uint32(util::vector_tile::VERSION_TAG, 2); // version
point_layer_writer.add_string(util::vector_tile::NAME_TAG, "turns"); // name

2
unit_tests/library/tile.cpp
View File

@ -205,7 +205,7 @@ BOOST_AUTO_TEST_CASE(test_tile)
}
BOOST_CHECK_EQUAL(number_of_turn_keys, 3);
BOOST_CHECK_EQUAL(number_of_turns_found, 137);
BOOST_CHECK_EQUAL(number_of_turns_found, 732);
}
BOOST_AUTO_TEST_SUITE_END()