fix(editor): the whole-scenery grade fit takes spans a few metres apart for one bridge, leaves the culverts on the embankment and ends a bridge at a joint by its abutment

Bridged stretches less than 5 m apart are merged into one bridge on its piers, and those shorter than 3 m, a ditch or a
culvert under the embankment, are no bridge. A bridge end within 1 m of a joint of the route or a break of the line moves to
it, so the cut leaves no sliver of a path by the abutment. Against the OpenStreetMap railway bridges the marked share stays
the same (lk91 60 of 66, TG 90 of 104); the places with nothing under them in the map fall from 6 to 4 on lk91 and from 18
to 12 on TG, and the bridge paths shorter than 1 m from 9 to 0 and from 11 to 1.

application/editormodenmt.cpp

@@ -2073,10 +2073,22 @@ bool editor_mode::nmt_fit_line(TTrack &Track)
 	// are cut off and set to the bridge, the formation is laid up to it, the ground under it stays as the model has it
 	double constexpr kBridged{1.0}; // m
 	double constexpr kAbutment{100.0}; // per mille
+	// spans a few metres apart are one bridge on its piers; what is shorter than that is a culvert under the embankment
+	double constexpr kPier{5.0}; // m
+	double constexpr kCulvert{3.0}; // m
 	std::vector<double> heights(count);
 	for (std::size_t i = 0; i < count; ++i)
 		heights[i] = profile::elevation(fitted_line, sampled[i]);
-	auto const bridges{profile::bridged(sampled, heights, model, kBridged, kAbutment)};
+	std::vector<profile::departure> bridges;
+	for (auto const &stretch : profile::bridged(sampled, heights, model, kBridged, kAbutment))
+		if (false == bridges.empty() && stretch.from - bridges.back().to < kPier)
+		{
+			bridges.back().to = stretch.to;
+			bridges.back().depth = std::min(bridges.back().depth, stretch.depth);
+		}
+		else
+			bridges.push_back(stretch);
+	bridges.erase(std::remove_if(bridges.begin(), bridges.end(), [&](profile::departure const &Bridge) { return Bridge.to - Bridge.from < kCulvert; }), bridges.end());
 	profile_apply(false, bridges);
 	auto const applied{profile.error.empty()};
 	// where the line parts from the model: under it a gap, a bridge or a viaduct, over it a wall or a structure above the track

application/editormodeprofile.cpp

@@ -1476,7 +1476,18 @@ void editor_mode::profile_apply(bool const Terrain, std::vector<profile::departu
 	std::vector<std::pair<TTrack *, editor_track::state>> states;
 	std::vector<TTrack *> created;
 	auto cuts{profile::breaks(line)};
-	for (auto const &bridge : Bridges)
+	// a bridge ends at a joint or a break of the line by its abutment rather than leave a sliver of a path there
+	double constexpr kBridgeSnap{1.0}; // m
+	auto joints{cuts};
+	for (auto const &span : state.route.spans)
+		joints.insert(joints.end(), {span.from, span.to});
+	auto bridges{Bridges};
+	for (auto &bridge : bridges)
+		for (auto *end : {&bridge.from, &bridge.to})
+			if (auto const nearest{std::min_element(joints.begin(), joints.end(), [&](double const A, double const B) { return std::abs(A - *end) < std::abs(B - *end); })};
+			    nearest != joints.end() && std::abs(*nearest - *end) <= kBridgeSnap)
+				*end = *nearest;
+	for (auto const &bridge : bridges)
 		cuts.insert(cuts.end(), {bridge.from, bridge.to});
 	std::sort(cuts.begin(), cuts.end());
 	auto const gaps{editor_track::apply_profile(
@@ -1486,7 +1497,7 @@ void editor_mode::profile_apply(bool const Terrain, std::vector<profile::departu
 	std::size_t bridged{0};
 	for (auto const &span : state.route.spans)
 		if (span.track->eEnvironment != e_bridge && span.track->eEnvironment != e_tunnel
-		    && std::any_of(Bridges.begin(), Bridges.end(), [&](profile::departure const &Bridge) { return span.from >= Bridge.from - kBridgeEnd && span.to <= Bridge.to + kBridgeEnd; }))
+		    && std::any_of(bridges.begin(), bridges.end(), [&](profile::departure const &Bridge) { return span.from >= Bridge.from - kBridgeEnd && span.to <= Bridge.to + kBridgeEnd; }))
 		{
 			span.track->eEnvironment = e_bridge;
 			++bridged;