Allow thirty percent checked coastal preference detours

Author: woensug-choi

README.ko.md

@@ -63,7 +63,7 @@ path = planner.route(start, goal)
 
 목적지 항구로 진행할 때만 해안 가까운 경로를 우선합니다. 마지막 구간은
 항로 목표와 항구를 향해야 합니다. 같은 후속 목표까지 검증한 짧은 경로보다
-전체 거리가 15% 넘게 늘어나면 일반 수상 경로를 사용합니다.
+전체 거리가 30% 넘게 늘어나면 일반 수상 경로를 사용합니다.
 육지나 여울을 피하려면 만과 섬을 돌아갈 수 있습니다.
 항구와 필수 통과점은 도착 조건을 유지합니다.
 
@@ -76,7 +76,7 @@ path = planner.route(start, goal)
 | 수상 차량 로컬 수심 여유 | 1.5 m |
 | 수상 차량 반경 + 추적 여유 | 3.5 m + 4 m |
 | 해안 선호 거리 | 250 m |
-| 해안 선호에 따른 추가 거리 한도 | 15% |
+| 해안 선호에 따른 추가 거리 한도 | 30% |
 | 해안 지역 여유 폭 / 수심 | 40 m / 2 m |
 | 도착 반경 | 300 m |
 | 도착 목표 검사 | 반경 350 m / 수심 3 m |

README.md

@@ -63,7 +63,7 @@ checked segment. Longitude wrapping supports the international date line.
 
 Coastal lookahead favours shore only while progressing toward the destination
 port. Its final stretch must approach both the course target and the port.
-The full coastal route may add at most 15% to a shorter checked route to the
+The full coastal route may add at most 30% to a shorter checked route to the
 same onward target. Longer scenic detours use the ordinary water route instead.
 Land and shallow water can still require a detour around bays or islands.
 Ports and required passage points retain their arrival checks.
@@ -77,7 +77,7 @@ shortened route preserves its checked exit.
 | Surface local depth clearance | 1.5 m |
 | Surface hull radius + tracking margin | 3.5 m + 4 m |
 | Coastal preferred distance | 250 m |
-| Maximum extra distance for coastal preference | 15% |
+| Maximum extra distance for coastal preference | 30% |
 | Coastal regional buffer / depth | 40 m / 2 m |
 | Arrival radius | 300 m |
 | Arrival target screening | 350 m buffer / 3 m depth |

src/posim_routing/coastal.py

@@ -25,7 +25,7 @@
 MINIMUM_DEPTH_M = 2.
 REGIONAL_BUFFER_M = 40.
 WAYPOINT_FORMAT = "checked-segment-ends-v2-destination-progress"
-MAXIMUM_COASTAL_DETOUR_RATIO = 1.15
+MAXIMUM_COASTAL_DETOUR_RATIO = 1.30
 
 
 def sphere(coordinates):
@@ -122,7 +122,7 @@ def coastal_approach(start, target, shore, progress_target=None):
 def coastal_corridor(terrain, spec, start, target, timeout=25., guard=None, progress_target=None):
     """Return a coastal or shorter checked water path, or retain the course.
 
-    A checked coast preference may add at most 15 percent to the shortest
+    A checked coast preference may add at most 30 percent to the shortest
     checked route to the same onward goal. Its final stretch must approach
     both that goal and the destination. Required land detours remain available
     through the ordinary planner. Close to a waypoint, exact arrival wins.

tests/test_coastal_navigation.py

@@ -49,7 +49,7 @@ def test_stays_near_coast_and_progresses(self):
         self.assertEqual(plan['mode'], 'coastal')
         self.assertLess(abs(plan['endpoint_standoff_m']-STANDOFF_M), 200)
         self.assertGreater(plan['progress_to_course_waypoint_m'], 1000)
-        self.assertLessEqual(plan['coastal_through_length_m'], plan['shortest_checked_length_m']*1.15)
+        self.assertLessEqual(plan['coastal_through_length_m'], plan['shortest_checked_length_m']*1.30)
         self.assert_swept_safe(terrain, start, plan)
 
     def test_close_safe_start_is_not_rejected_by_an_extra_grid_ring(self):
@@ -72,13 +72,15 @@ def test_offshore_start_does_not_take_a_scenic_detour(self):
     def test_headland_cannot_be_shortcut(self):
         terrain = grid(headland=True)
         start = geo(800, -4000)
-        # Land avoidance remains mandatory when scenic preference is rejected.
+        # The relaxed coastal preference still requires going around land.
         target = geo(800, 9000)
         plan = coastal_corridor(terrain, SPEC, start, target)
-        self.assertEqual(plan['mode'],'detour')
-        points = np.array([FORWARD.transform(*p) for p in plan['points']])
+        self.assertEqual(plan['mode'],'coastal')
+        self.assertLessEqual(plan['coastal_through_length_m'], plan['shortest_checked_length_m']*1.30)
+        through = plan['points']+plan['onward_points']
+        points = np.array([FORWARD.transform(*p) for p in through])
         self.assertGreater(points[:, 0].max(), 1800+REGIONAL_BUFFER_M)
-        self.assert_swept_safe(terrain, start, plan)
+        self.assert_swept_safe(terrain, start, dict(points=through))
 
     def test_closed_bay_requires_an_onward_water_exit(self):
         terrain = grid()
@@ -164,7 +166,12 @@ def test_distant_coast_approach_advances_without_changing_course_target(self):
         self.assertEqual(target,geo(0,-90000))
         self.assertIsNone(coastal_approach(geo(800,0),target,geo(0,0)))
         self.assertIsNone(coastal_approach(geo(30000,0),geo(90000,0),geo(0,0)))
-        self.assertIsNone(coastal_approach(start,target,geo(0,-12000)))
+        relaxed=coastal_approach(start,target,geo(0,-12000))
+        self.assertIsNotNone(relaxed)
+        travel=distance(start,relaxed)
+        progress=distance(start,target)-distance(relaxed,target)
+        self.assertGreaterEqual(progress,travel/1.30)
+        self.assertLess(progress,travel/1.15)
         self.assertIsNone(coastal_approach(start,target,shore,progress_target=geo(90000,0)))
 
     def test_real_progressive_shore_excludes_backward_coast(self):