From 030a6eecc94e5e328e9236ac8dd9adb515898bed Mon Sep 17 00:00:00 2001
From: atsunatsu <atsunatsu@users.noreply.github.com>
Date: Thu, 10 Sep 2026 01:05:25 +0800
Subject: [PATCH] =?UTF-8?q?fix(map):=20split=20antimeridian=20edges=20inst?=
 =?UTF-8?q?ead=20of=20dropping=20=E2=80=94=20closes=20WAZ=20zone=201/19/31?=
 =?UTF-8?q?/32=20outlines?=
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splitRingAtAntimeridian used to drop any edge crossing ±180°, leaving
visible gaps in WAZ zone outlines (zone 31's 40°N Pacific boundary,
zone 1/19's polar arcs, zone 32's Antarctic arc). The edge is now split
in two at ±180° with interpolated latitude, each half kept in its own
segment, so outlines close across the map's left/right edges.
normalizeLon now maps to (-180, 180] so edges ENDING on the
antimeridian are not mistaken for crossings.
---
 .../feature/map/AwardBoundaryOverlay.kt       | 24 ++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/feature/map/src/main/java/com/rtbishop/look4sat/feature/map/AwardBoundaryOverlay.kt b/feature/map/src/main/java/com/rtbishop/look4sat/feature/map/AwardBoundaryOverlay.kt
index ee49af9b..71cc892e 100644
--- a/feature/map/src/main/java/com/rtbishop/look4sat/feature/map/AwardBoundaryOverlay.kt
+++ b/feature/map/src/main/java/com/rtbishop/look4sat/feature/map/AwardBoundaryOverlay.kt
@@ -261,9 +261,23 @@ class AwardBoundaryOverlay : Overlay() {
             val prevLon = pts[i - 1][0]
             val lon = pts[i][0]
             if (abs(lon - prevLon) > 180.0) {
-                // Crossed the antimeridian: start a fresh segment.
+                // Crossed the antimeridian. Do NOT drop this edge — that would
+                // leave a visible gap in the outline (WAZ Pacific zones 1/19/
+                // 31/32, e.g. zone 31's 40°N boundary from 130°W to 160°E).
+                // Split the edge IN TWO at ±180 instead: each half stays in its
+                // own segment, so the outline closes across the map's left and
+                // right edges. The crossing latitude is interpolated along the
+                // edge (constant for latitude-aligned edges).
+                val a = pts[i - 1]
+                val b = pts[i]
+                val span = 360.0 - abs(lon - prevLon) // shortest angular distance
+                val edgeLon = if (prevLon < lon) -180.0 else 180.0 // side being crossed
+                val t = abs(edgeLon - prevLon) / span
+                val latAt = a[1] + (b[1] - a[1]) * t
+                cur.add(doubleArrayOf(edgeLon, latAt))
                 if (cur.size >= 2) segments.add(cur)
                 cur = mutableListOf()
+                cur.add(doubleArrayOf(-edgeLon, latAt))
             }
             cur.add(pts[i])
         }
@@ -378,8 +392,12 @@ class AwardBoundaryOverlay : Overlay() {
 
     private fun normalizeLon(lon: Double): Double {
         var l = lon % 360.0
-        if (l >= 180.0) l -= 360.0
-        if (l < -180.0) l += 360.0
+        // Normalize into (-180, 180] — +180, not -180. An edge whose endpoint
+        // sits ON the antimeridian (e.g. a ring starting at -180°) must not be
+        // seen as a >180° jump away from a nearby 165° vertex; keeping the
+        // antimeridian value as +180 makes such edges short and un-split.
+        if (l <= -180.0) l += 360.0
+        if (l > 180.0) l -= 360.0
         return l
     }