separate intersection generation and intersection normalization

2016-11-09 16:52:22 +01:00
parent e84a0ea37c
commit 827a1fbd7a
11 changed files with 624 additions and 512 deletions
@@ -0,0 +1,101 @@
+#ifndef OSRM_EXTRACTOR_GUIDANCE_INTERSECTION_NORMALIZER_HPP_
+#define OSRM_EXTRACTOR_GUIDANCE_INTERSECTION_NORMALIZER_HPP_
+
+#include "util/typedefs.hpp"
+
+#include "util/attributes.hpp"
+
+#include "extractor/guidance/coordinate_extractor.hpp"
+#include "extractor/guidance/intersection.hpp"
+#include "extractor/guidance/intersection_generator.hpp"
+#include "extractor/query_node.hpp"
+
+#include "extractor/suffix_table.hpp"
+#include "util/name_table.hpp"
+
+#include <vector>
+
+namespace osrm
+{
+namespace extractor
+{
+namespace guidance
+{
+
+/*
+ * An intersection is a central part in computing guidance decisions. However the model in OSM and
+ * the view we want to use in guidance are not necessarily the same thing. We have to account for
+ * some models that are chosen explicitly in OSM and that don't actually describe how a human would
+ * experience an intersection.
+ *
+ * For example, if a small pedestrian island is located at a traffic light right in the middle of a
+ * road, OSM tends to model the road as two separate ways. A human would consider these two ways a
+ * single road, though. In this normalizer, we try to account for these subtle differences between
+ * OSM data and human perception to improve our decision base for guidance later on.
+ */
+class IntersectionNormalizer
+{
+  public:
+    IntersectionNormalizer(const util::NodeBasedDynamicGraph &node_based_graph,
+                           const std::vector<extractor::QueryNode> &node_coordinates,
+                           const util::NameTable &name_table,
+                           const SuffixTable &street_name_suffix_table,
+                           const IntersectionGenerator &intersection_generator);
+
+    // The function takes an intersection an converts it to a `perceived` intersection which closer
+    // represents how a human might experience the intersection
+    OSRM_ATTR_WARN_UNUSED
+    Intersection operator()(const NodeID node_at_intersection, Intersection intersection) const;
+
+  private:
+    const util::NodeBasedDynamicGraph &node_based_graph;
+    const std::vector<extractor::QueryNode> &node_coordinates;
+    const util::NameTable &name_table;
+    const SuffixTable &street_name_suffix_table;
+
+    const IntersectionGenerator &intersection_generator;
+
+    // check if two indices in an intersection can be seen as a single road in the perceived
+    // intersection representation. See below for an example. Utility function for
+    // MergeSegregatedRoads
+    bool CanMerge(const NodeID intersection_node,
+                  const Intersection &intersection,
+                  std::size_t first_index,
+                  std::size_t second_index) const;
+
+    // Merge segregated roads to omit invalid turns in favor of treating segregated roads as
+    // one.
+    // This function combines roads the following way:
+    //
+    //     *                           *
+    //     *        is converted to    *
+    //   v   ^                         +
+    //   v   ^                         +
+    //
+    // The treatment results in a straight turn angle of 180º rather than a turn angle of approx
+    // 160
+    OSRM_ATTR_WARN_UNUSED
+    Intersection MergeSegregatedRoads(const NodeID intersection_node,
+                                      Intersection intersection) const;
+
+    // The counterpiece to mergeSegregatedRoads. While we can adjust roads that split up at the
+    // intersection itself, it can also happen that intersections are connected to joining roads.
+    //
+    //     *                           *
+    //     *        is converted to    *
+    //   v   a ---                     a ---
+    //   v   ^                         +
+    //   v   ^                         +
+    //       b
+    //
+    // for the local view of b at a.
+    OSRM_ATTR_WARN_UNUSED
+    Intersection AdjustForJoiningRoads(const NodeID node_at_intersection,
+                                       Intersection intersection) const;
+};
+
+} // namespace guidance
+} // namespace extractor
+} // namespace osrm
+
+#endif /* OSRM_EXTRACTOR_GUIDANCE_INTERSECTION_NORMALIZER_HPP_ */