Merge pull request 'release: 2026-03-24.2 (폴리곤 서버사이드 이관)' (#179) from develop into main

2026-03-24 14:09:37 +09:00 · 2026-03-24 14:09:37 +09:00 · 03747d3c63
--- a/backend/src/main/java/gc/mda/kcg/config/CacheConfig.java
+++ b/backend/src/main/java/gc/mda/kcg/config/CacheConfig.java
@ -21,6 +21,7 @@ public class CacheConfig {
    public static final String SEISMIC = "seismic";
    public static final String PRESSURE = "pressure";
    public static final String VESSEL_ANALYSIS = "vessel-analysis";
+    public static final String GROUP_POLYGONS = "group-polygons";

    @Bean
    public CacheManager cacheManager() {
@ -29,7 +30,8 @@ public class CacheConfig {
                OSINT_IRAN, OSINT_KOREA,
                SATELLITES,
                SEISMIC, PRESSURE,
-                VESSEL_ANALYSIS
+                VESSEL_ANALYSIS,
+                GROUP_POLYGONS
        );
        manager.setCaffeine(Caffeine.newBuilder()
                .expireAfterWrite(2, TimeUnit.DAYS)
--- a/backend/src/main/java/gc/mda/kcg/domain/fleet/GroupPolygonController.java
+++ b/backend/src/main/java/gc/mda/kcg/domain/fleet/GroupPolygonController.java
@ -0,0 +1,51 @@
+package gc.mda.kcg.domain.fleet;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.Map;
+
+@RestController
+@RequestMapping("/api/vessel-analysis/groups")
+@RequiredArgsConstructor
+public class GroupPolygonController {
+
+    private final GroupPolygonService groupPolygonService;
+
+    /**
+     * 전체 그룹 폴리곤 목록 (최신 스냅샷, 5분 캐시)
+     */
+    @GetMapping
+    public ResponseEntity<Map<String, Object>> getGroups() {
+        List<GroupPolygonDto> groups = groupPolygonService.getLatestGroups();
+        return ResponseEntity.ok(Map.of(
+                "count", groups.size(),
+                "items", groups
+        ));
+    }
+
+    /**
+     * 특정 그룹 상세 (멤버, 면적, 폴리곤 생성 근거)
+     */
+    @GetMapping("/{groupKey}/detail")
+    public ResponseEntity<GroupPolygonDto> getGroupDetail(@PathVariable String groupKey) {
+        GroupPolygonDto detail = groupPolygonService.getGroupDetail(groupKey);
+        if (detail == null) {
+            return ResponseEntity.notFound().build();
+        }
+        return ResponseEntity.ok(detail);
+    }
+
+    /**
+     * 특정 그룹 히스토리 (시간별 폴리곤 변화)
+     */
+    @GetMapping("/{groupKey}/history")
+    public ResponseEntity<List<GroupPolygonDto>> getGroupHistory(
+            @PathVariable String groupKey,
+            @RequestParam(defaultValue = "24") int hours) {
+        List<GroupPolygonDto> history = groupPolygonService.getGroupHistory(groupKey, hours);
+        return ResponseEntity.ok(history);
+    }
+}
--- a/backend/src/main/java/gc/mda/kcg/domain/fleet/GroupPolygonDto.java
+++ b/backend/src/main/java/gc/mda/kcg/domain/fleet/GroupPolygonDto.java
@ -0,0 +1,27 @@
+package gc.mda.kcg.domain.fleet;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import lombok.Builder;
+import lombok.Getter;
+
+import java.util.List;
+import java.util.Map;
+
+@Getter
+@Builder
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class GroupPolygonDto {
+    private String groupType;
+    private String groupKey;
+    private String groupLabel;
+    private String snapshotTime;
+    private Object polygon;       // GeoJSON Polygon (parsed from ST_AsGeoJSON)
+    private double centerLat;
+    private double centerLon;
+    private double areaSqNm;
+    private int memberCount;
+    private String zoneId;
+    private String zoneName;
+    private List<Map<String, Object>> members;
+    private String color;
+}
--- a/backend/src/main/java/gc/mda/kcg/domain/fleet/GroupPolygonService.java
+++ b/backend/src/main/java/gc/mda/kcg/domain/fleet/GroupPolygonService.java
@ -0,0 +1,131 @@
+package gc.mda.kcg.domain.fleet;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import gc.mda.kcg.config.CacheConfig;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.cache.Cache;
+import org.springframework.cache.CacheManager;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Service;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.List;
+import java.util.Map;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class GroupPolygonService {
+
+    private final JdbcTemplate jdbcTemplate;
+    private final CacheManager cacheManager;
+    private final ObjectMapper objectMapper;
+
+    private static final String LATEST_GROUPS_SQL = """
+            SELECT group_type, group_key, group_label, snapshot_time,
+                   ST_AsGeoJSON(polygon) AS polygon_geojson,
+                   ST_Y(center_point) AS center_lat, ST_X(center_point) AS center_lon,
+                   area_sq_nm, member_count, zone_id, zone_name, members, color
+            FROM kcg.group_polygon_snapshots
+            WHERE snapshot_time = (SELECT MAX(snapshot_time) FROM kcg.group_polygon_snapshots)
+            ORDER BY group_type, member_count DESC
+            """;
+
+    private static final String GROUP_DETAIL_SQL = """
+            SELECT group_type, group_key, group_label, snapshot_time,
+                   ST_AsGeoJSON(polygon) AS polygon_geojson,
+                   ST_Y(center_point) AS center_lat, ST_X(center_point) AS center_lon,
+                   area_sq_nm, member_count, zone_id, zone_name, members, color
+            FROM kcg.group_polygon_snapshots
+            WHERE group_key = ?
+            ORDER BY snapshot_time DESC
+            LIMIT 1
+            """;
+
+    private static final String GROUP_HISTORY_SQL = """
+            SELECT group_type, group_key, group_label, snapshot_time,
+                   ST_AsGeoJSON(polygon) AS polygon_geojson,
+                   ST_Y(center_point) AS center_lat, ST_X(center_point) AS center_lon,
+                   area_sq_nm, member_count, zone_id, zone_name, members, color
+            FROM kcg.group_polygon_snapshots
+            WHERE group_key = ? AND snapshot_time > NOW() - CAST(? || ' hours' AS INTERVAL)
+            ORDER BY snapshot_time DESC
+            """;
+
+    /**
+     * 최신 스냅샷의 전체 그룹 폴리곤 목록 (5분 캐시).
+     */
+    @SuppressWarnings("unchecked")
+    public List<GroupPolygonDto> getLatestGroups() {
+        Cache cache = cacheManager.getCache(CacheConfig.GROUP_POLYGONS);
+        if (cache != null) {
+            Cache.ValueWrapper wrapper = cache.get("data");
+            if (wrapper != null) {
+                return (List<GroupPolygonDto>) wrapper.get();
+            }
+        }
+
+        List<GroupPolygonDto> results = jdbcTemplate.query(LATEST_GROUPS_SQL, this::mapRow);
+
+        if (cache != null) {
+            cache.put("data", results);
+        }
+        return results;
+    }
+
+    /**
+     * 특정 그룹의 최신 상세 정보.
+     */
+    public GroupPolygonDto getGroupDetail(String groupKey) {
+        List<GroupPolygonDto> results = jdbcTemplate.query(GROUP_DETAIL_SQL, this::mapRow, groupKey);
+        return results.isEmpty() ? null : results.get(0);
+    }
+
+    /**
+     * 특정 그룹의 시간별 히스토리.
+     */
+    public List<GroupPolygonDto> getGroupHistory(String groupKey, int hours) {
+        return jdbcTemplate.query(GROUP_HISTORY_SQL, this::mapRow, groupKey, String.valueOf(hours));
+    }
+
+    private GroupPolygonDto mapRow(ResultSet rs, int rowNum) throws SQLException {
+        Object polygonObj = null;
+        String polygonJson = rs.getString("polygon_geojson");
+        if (polygonJson != null) {
+            try {
+                polygonObj = objectMapper.readValue(polygonJson, new TypeReference<Map<String, Object>>() {});
+            } catch (Exception e) {
+                log.warn("Failed to parse polygon GeoJSON: {}", e.getMessage());
+            }
+        }
+
+        List<Map<String, Object>> members = List.of();
+        String membersJson = rs.getString("members");
+        if (membersJson != null) {
+            try {
+                members = objectMapper.readValue(membersJson, new TypeReference<>() {});
+            } catch (Exception e) {
+                log.warn("Failed to parse members JSON: {}", e.getMessage());
+            }
+        }
+
+        return GroupPolygonDto.builder()
+                .groupType(rs.getString("group_type"))
+                .groupKey(rs.getString("group_key"))
+                .groupLabel(rs.getString("group_label"))
+                .snapshotTime(rs.getString("snapshot_time"))
+                .polygon(polygonObj)
+                .centerLat(rs.getDouble("center_lat"))
+                .centerLon(rs.getDouble("center_lon"))
+                .areaSqNm(rs.getDouble("area_sq_nm"))
+                .memberCount(rs.getInt("member_count"))
+                .zoneId(rs.getString("zone_id"))
+                .zoneName(rs.getString("zone_name"))
+                .members(members)
+                .color(rs.getString("color"))
+                .build();
+    }
+}
--- a/database/migration/009_group_polygons.sql
+++ b/database/migration/009_group_polygons.sql
@ -0,0 +1,49 @@
+-- 009: 선단/어구그룹 폴리곤 스냅샷 테이블
+-- 5분 주기 APPEND, 7일 보존
+
+SET search_path TO kcg, public;
+
+CREATE TABLE IF NOT EXISTS kcg.group_polygon_snapshots (
+  id              BIGSERIAL PRIMARY KEY,
+
+  -- 그룹 식별
+  group_type      VARCHAR(20) NOT NULL,         -- FLEET | GEAR_IN_ZONE | GEAR_OUT_ZONE
+  group_key       VARCHAR(100) NOT NULL,         -- fleet: company_id, gear: parent_name
+  group_label     TEXT,                           -- 표시명 (회사명 또는 모선명)
+
+  -- 스냅샷 시각
+  snapshot_time   TIMESTAMPTZ NOT NULL,
+
+  -- PostGIS geometry
+  polygon         geometry(Polygon, 4326),       -- convex hull + buffer (3점 미만 시 NULL)
+  center_point    geometry(Point, 4326),          -- 중심점
+
+  -- 지표
+  area_sq_nm      DOUBLE PRECISION DEFAULT 0,    -- 면적 (제곱 해리)
+  member_count    INT NOT NULL DEFAULT 0,         -- 소속 선박/어구 수
+
+  -- 수역 분류 (어구그룹용)
+  zone_id         VARCHAR(20),                    -- ZONE_I ~ ZONE_IV | OUTSIDE
+  zone_name       TEXT,
+
+  -- 멤버 상세 (JSONB 배열)
+  members         JSONB NOT NULL DEFAULT '[]',
+  -- [{mmsi, name, lat, lon, sog, cog, role, isParent}]
+
+  -- 색상 힌트
+  color           VARCHAR(20),
+
+  created_at      TIMESTAMPTZ DEFAULT NOW()
+);
+
+-- 조회 성능 인덱스
+CREATE INDEX IF NOT EXISTS idx_gps_type_time
+  ON kcg.group_polygon_snapshots(group_type, snapshot_time DESC);
+CREATE INDEX IF NOT EXISTS idx_gps_key_time
+  ON kcg.group_polygon_snapshots(group_key, snapshot_time DESC);
+CREATE INDEX IF NOT EXISTS idx_gps_snapshot_time
+  ON kcg.group_polygon_snapshots(snapshot_time DESC);
+
+-- 공간 인덱스
+CREATE INDEX IF NOT EXISTS idx_gps_polygon_gist
+  ON kcg.group_polygon_snapshots USING GIST(polygon);
--- a/docs/RELEASE-NOTES.md
+++ b/docs/RELEASE-NOTES.md
@ -4,6 +4,21 @@

 ## [Unreleased]

+## [2026-03-24.2]
+
+### 추가
+- 선단/어구그룹 폴리곤 서버사이드 생성: Shapely convex hull + buffer → PostGIS 저장
+- DB migration 009: group_polygon_snapshots 테이블 (5분 APPEND, 7일 보존)
+- Backend API: GET /api/vessel-analysis/groups (목록/상세/히스토리)
+- useGroupPolygons 훅: 5분 폴링 (fleet/gearInZone/gearOutZone)
+
+### 변경
+- FleetClusterLayer: 클라이언트 convexHull/padPolygon 제거 → API GeoJSON 직접 렌더링
+- 프론트 어구그룹 탐지(regex+거리 클러스터링) Python 이관
+
+### 수정
+- 불법어선 탭 복원 (임시 숨김 해제)
+
 ## [2026-03-24.1]

 ### 추가
--- a/frontend/src/components/korea/FleetClusterLayer.tsx
+++ b/frontend/src/components/korea/FleetClusterLayer.tsx
@ -6,8 +6,7 @@ import type { MapLayerMouseEvent } from 'maplibre-gl';
 import type { Ship, VesselAnalysisDto } from '../../types';
 import { fetchFleetCompanies } from '../../services/vesselAnalysis';
 import type { FleetCompany } from '../../services/vesselAnalysis';
-import { classifyFishingZone } from '../../utils/fishingAnalysis';
-import { convexHull, padPolygon, clusterColor } from '../../utils/geometry';
+import type { UseGroupPolygonsResult } from '../../hooks/useGroupPolygons';

 export interface SelectedGearGroupData {
  parent: Ship | null;
@ -29,31 +28,13 @@ interface Props {
  onFleetZoom?: (bounds: { minLat: number; maxLat: number; minLng: number; maxLng: number }) => void;
  onSelectedGearChange?: (data: SelectedGearGroupData | null) => void;
  onSelectedFleetChange?: (data: SelectedFleetData | null) => void;
+  groupPolygons?: UseGroupPolygonsResult;
 }

-// GeoJSON feature에 color 속성으로 주입
-interface ClusterPolygonFeature {
-  type: 'Feature';
-  id: number;
-  properties: { clusterId: number; color: string };
-  geometry: { type: 'Polygon'; coordinates: [number, number][][] };
-}
-
-interface ClusterLineFeature {
-  type: 'Feature';
-  id: number;
-  properties: { clusterId: number; color: string };
-  geometry: { type: 'LineString'; coordinates: [number, number][] };
-}
-
-type ClusterFeature = ClusterPolygonFeature | ClusterLineFeature;
-
 const EMPTY_ANALYSIS = new globalThis.Map<string, VesselAnalysisDto>();
-const EMPTY_CLUSTERS = new globalThis.Map<number, string[]>();

-export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, clusters: clustersProp, onShipSelect, onFleetZoom, onSelectedGearChange, onSelectedFleetChange }: Props) {
+export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, onShipSelect, onFleetZoom, onSelectedGearChange, onSelectedFleetChange, groupPolygons }: Props) {
  const analysisMap = analysisMapProp ?? EMPTY_ANALYSIS;
-  const clusters = clustersProp ?? EMPTY_CLUSTERS;
  const [companies, setCompanies] = useState<Map<number, FleetCompany>>(new Map());
  const [expandedFleet, setExpandedFleet] = useState<number | null>(null);
  const [sectionExpanded, setSectionExpanded] = useState<Record<string, boolean>>({
@ -67,8 +48,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
  const [hoverTooltip, setHoverTooltip] = useState<{ lng: number; lat: number; type: 'fleet' | 'gear'; id: number | string } | null>(null);
  const { current: mapRef } = useMap();
  const registeredRef = useRef(false);
-  // dataRef는 shipMap/gearGroupMap 선언 이후에 갱신 (아래 참조)
-  const dataRef = useRef<{ clusters: Map<number, string[]>; shipMap: Map<string, Ship>; gearGroupMap: Map<string, { parent: Ship | null; gears: Ship[] }>; onFleetZoom: Props['onFleetZoom'] }>({ clusters, shipMap: new Map(), gearGroupMap: new Map(), onFleetZoom });
+  const dataRef = useRef<{ shipMap: Map<string, Ship>; groupPolygons: UseGroupPolygonsResult | undefined; onFleetZoom: Props['onFleetZoom'] }>({ shipMap: new Map(), groupPolygons, onFleetZoom });

  useEffect(() => {
    fetchFleetCompanies().then(setCompanies).catch(() => {});
@ -107,17 +87,15 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
      if (cid == null) return;
      const d = dataRef.current;
      setExpandedFleet(prev => prev === cid ? null : cid);
-      setExpanded(true);
-      const mmsiList = d.clusters.get(cid) ?? [];
-      if (mmsiList.length === 0) return;
+      setSectionExpanded(prev => ({ ...prev, fleet: true }));
+      const group = d.groupPolygons?.fleetGroups.find(g => Number(g.groupKey) === cid);
+      if (!group || group.members.length === 0) return;
      let minLat = Infinity, maxLat = -Infinity, minLng = Infinity, maxLng = -Infinity;
-      for (const mmsi of mmsiList) {
-        const ship = d.shipMap.get(mmsi);
-        if (!ship) continue;
-        if (ship.lat < minLat) minLat = ship.lat;
-        if (ship.lat > maxLat) maxLat = ship.lat;
-        if (ship.lng < minLng) minLng = ship.lng;
-        if (ship.lng > maxLng) maxLng = ship.lng;
+      for (const m of group.members) {
+        if (m.lat < minLat) minLat = m.lat;
+        if (m.lat > maxLat) maxLat = m.lat;
+        if (m.lon < minLng) minLng = m.lon;
+        if (m.lon > maxLng) maxLng = m.lon;
      }
      if (minLat !== Infinity) d.onFleetZoom?.({ minLat, maxLat, minLng, maxLng });
    };
@ -147,16 +125,17 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
      requestAnimationFrame(() => {
        document.getElementById(`gear-row-${name}`)?.scrollIntoView({ behavior: 'smooth', block: 'start' });
      });
-      const entry = d.gearGroupMap.get(name);
-      if (!entry) return;
-      const all: Ship[] = [...entry.gears];
-      if (entry.parent) all.push(entry.parent);
+      const allGroups = d.groupPolygons
+        ? [...d.groupPolygons.gearInZoneGroups, ...d.groupPolygons.gearOutZoneGroups]
+        : [];
+      const group = allGroups.find(g => g.groupKey === name);
+      if (!group || group.members.length === 0) return;
      let minLat = Infinity, maxLat = -Infinity, minLng = Infinity, maxLng = -Infinity;
-      for (const s of all) {
-        if (s.lat < minLat) minLat = s.lat;
-        if (s.lat > maxLat) maxLat = s.lat;
-        if (s.lng < minLng) minLng = s.lng;
-        if (s.lng > maxLng) maxLng = s.lng;
+      for (const m of group.members) {
+        if (m.lat < minLat) minLat = m.lat;
+        if (m.lat > maxLat) maxLat = m.lat;
+        if (m.lon < minLng) minLng = m.lon;
+        if (m.lon > maxLng) maxLng = m.lon;
      }
      if (minLat !== Infinity) d.onFleetZoom?.({ minLat, maxLat, minLng, maxLng });
    };
@ -188,29 +167,6 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
    }
  }, [mapRef]);

-  // 선박명 → mmsi 맵 (어구 매칭용)
-  const gearsByParent = useMemo(() => {
-    const map = new Map<string, Ship[]>(); // parent_mmsi → gears
-    const gearPattern = /^(.+?)_\d+_\d*$/;
-    const parentNames = new Map<string, string>(); // name → mmsi
-    for (const s of ships) {
-      if (s.name && !gearPattern.test(s.name)) {
-        parentNames.set(s.name.trim(), s.mmsi);
-      }
-    }
-    for (const s of ships) {
-      const m = s.name?.match(gearPattern);
-      if (!m) continue;
-      const parentMmsi = parentNames.get(m[1].trim());
-      if (parentMmsi) {
-        const arr = map.get(parentMmsi) ?? [];
-        arr.push(s);
-        map.set(parentMmsi, arr);
-      }
-    }
-    return map;
-  }, [ships]);
-
  // ships map (mmsi → Ship)
  const shipMap = useMemo(() => {
    const m = new Map<string, Ship>();
@ -218,56 +174,8 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
    return m;
  }, [ships]);

-  // 비허가 어구 클러스터: parentName → { parent: Ship | null, gears: Ship[] }
-  const gearGroupMap = useMemo(() => {
-    const gearPattern = /^(.+?)_\d+_\d+_?$/;
-    const MAX_DIST_DEG = 0.15; // ~10NM
-    const STALE_MS = 60 * 60_000;
-    const now = Date.now();
-
-    const nameToShip = new Map<string, Ship>();
-    for (const s of ships) {
-      const nm = (s.name || '').trim();
-      if (nm && !gearPattern.test(nm)) {
-        nameToShip.set(nm, s);
-      }
-    }
-
-    // 1단계: 같은 모선명 어구 수집 (60분 이내만)
-    const rawGroups = new Map<string, Ship[]>();
-    for (const s of ships) {
-      if (now - s.lastSeen > STALE_MS) continue;
-      const m = (s.name || '').match(gearPattern);
-      if (!m) continue;
-      const parentName = m[1].trim();
-      const arr = rawGroups.get(parentName) ?? [];
-      arr.push(s);
-      rawGroups.set(parentName, arr);
-    }
-
-    // 2단계: 거리 기반 서브 클러스터링 (같은 이름이라도 멀면 분리)
-    const map = new Map<string, { parent: Ship | null; gears: Ship[] }>();
-    for (const [parentName, gears] of rawGroups) {
-      const parent = nameToShip.get(parentName) ?? null;
-
-      // 기준점: 모선 있으면 모선 위치, 없으면 첫 어구
-      const anchor = parent ?? gears[0];
-      if (!anchor) continue;
-
-      const nearby = gears.filter(g => {
-        const dlat = Math.abs(g.lat - anchor.lat);
-        const dlng = Math.abs(g.lng - anchor.lng);
-        return dlat <= MAX_DIST_DEG && dlng <= MAX_DIST_DEG;
-      });
-
-      if (nearby.length === 0) continue;
-      map.set(parentName, { parent, gears: nearby });
-    }
-    return map;
-  }, [ships]);
-
-  // stale closure 방지 — shipMap/gearGroupMap 선언 이후 갱신
-  dataRef.current = { clusters, shipMap, gearGroupMap, onFleetZoom };
+  // stale closure 방지
+  dataRef.current = { shipMap, groupPolygons, onFleetZoom };

  // 선택된 어구 그룹 데이터를 부모에 전달 (deck.gl 렌더링용)
  useEffect(() => {
@ -275,13 +183,33 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
      onSelectedGearChange?.(null);
      return;
    }
-    const entry = gearGroupMap.get(selectedGearGroup);
-    if (entry) {
-      onSelectedGearChange?.({ parent: entry.parent, gears: entry.gears, groupName: selectedGearGroup });
-    } else {
+    const allGroups = groupPolygons
+      ? [...groupPolygons.gearInZoneGroups, ...groupPolygons.gearOutZoneGroups]
+      : [];
+    const group = allGroups.find(g => g.groupKey === selectedGearGroup);
+    if (!group) {
      onSelectedGearChange?.(null);
+      return;
    }
-  }, [selectedGearGroup, gearGroupMap, onSelectedGearChange]);
+    const parent = group.members.find(m => m.isParent);
+    const gears = group.members.filter(m => !m.isParent);
+    const toShip = (m: typeof group.members[0]): Ship => ({
+      mmsi: m.mmsi,
+      name: m.name,
+      lat: m.lat,
+      lng: m.lon,
+      heading: m.cog,
+      speed: m.sog,
+      course: m.cog,
+      category: 'fishing',
+      lastSeen: Date.now(),
+    });
+    onSelectedGearChange?.({
+      parent: parent ? toShip(parent) : null,
+      gears: gears.map(toShip),
+      groupName: selectedGearGroup,
+    });
+  }, [selectedGearGroup, groupPolygons, onSelectedGearChange]);

  // 선택된 선단 데이터를 부모에 전달 (deck.gl 강조 렌더링용)
  useEffect(() => {
@ -289,64 +217,115 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
      onSelectedFleetChange?.(null);
      return;
    }
-    const mmsiList = clusters.get(expandedFleet) ?? [];
-    const fleetShips = mmsiList.map(mmsi => shipMap.get(mmsi)).filter((s): s is Ship => !!s);
+    const group = groupPolygons?.fleetGroups.find(g => Number(g.groupKey) === expandedFleet);
    const company = companies.get(expandedFleet);
+    if (!group) {
+      onSelectedFleetChange?.(null);
+      return;
+    }
+    const fleetShips: Ship[] = group.members.map(m => ({
+      mmsi: m.mmsi,
+      name: m.name,
+      lat: m.lat,
+      lng: m.lon,
+      heading: m.cog,
+      speed: m.sog,
+      course: m.cog,
+      category: 'fishing',
+      lastSeen: Date.now(),
+    }));
    onSelectedFleetChange?.({
      clusterId: expandedFleet,
      ships: fleetShips,
-      companyName: company?.nameCn || `선단 #${expandedFleet}`,
+      companyName: company?.nameCn || group.groupLabel || `선단 #${expandedFleet}`,
    });
-  }, [expandedFleet, clusters, shipMap, companies, onSelectedFleetChange]);
+  }, [expandedFleet, groupPolygons, companies, onSelectedFleetChange]);

-  // 어구 그룹을 수역 내/외로 분류
-  const { inZoneGearGroups, outZoneGearGroups } = useMemo(() => {
-    const inZone: { name: string; parent: Ship | null; gears: Ship[]; zone: string }[] = [];
-    const outZone: { name: string; parent: Ship | null; gears: Ship[] }[] = [];
-    for (const [name, { parent, gears }] of gearGroupMap) {
-      const anchor = parent ?? gears[0];
-      if (!anchor) {
-        // 비허가 어구: 2개 이상일 때만 그룹으로 탐지
-        if (gears.length >= 2) outZone.push({ name, parent, gears });
-        continue;
-      }
-      const zoneInfo = classifyFishingZone(anchor.lat, anchor.lng);
-      if (zoneInfo.zone !== 'OUTSIDE') {
-        inZone.push({ name, parent, gears, zone: zoneInfo.name });
-      } else {
-        // 비허가 어구: 2개 이상일 때만 그룹으로 탐지
-        if (gears.length >= 2) outZone.push({ name, parent, gears });
-      }
-    }
-    inZone.sort((a, b) => b.gears.length - a.gears.length);
-    outZone.sort((a, b) => b.gears.length - a.gears.length);
-    return { inZoneGearGroups: inZone, outZoneGearGroups: outZone };
-  }, [gearGroupMap]);
+  // API 기반 어구 그룹 분류
+  const inZoneGearGroups = groupPolygons?.gearInZoneGroups ?? [];
+  const outZoneGearGroups = groupPolygons?.gearOutZoneGroups ?? [];

-  // 어구 클러스터 GeoJSON (수역 내: 붉은색, 수역 외: 오렌지)
-  // 비허가 어구(outZone)는 2개 이상만 폴리곤 생성
-  const gearClusterGeoJson = useMemo((): GeoJSON => {
-    const inZoneNames = new Set(inZoneGearGroups.map(g => g.name));
-    const outZoneNames = new Set(outZoneGearGroups.map(g => g.name));
+  // 선단 폴리곤 GeoJSON (서버 제공)
+  const fleetPolygonGeoJSON = useMemo((): GeoJSON => {
    const features: GeoJSON.Feature[] = [];
-    for (const [parentName, { parent, gears }] of gearGroupMap) {
-      // 비허가(outZone) 1개짜리는 폴리곤에서 제외
-      const isInZone = inZoneNames.has(parentName);
-      if (!isInZone && !outZoneNames.has(parentName)) continue;
-      const points: [number, number][] = gears.map(g => [g.lng, g.lat]);
-      if (parent) points.push([parent.lng, parent.lat]);
-      if (points.length < 3) continue;
-      const hull = convexHull(points);
-      const padded = padPolygon(hull, 0.01);
-      padded.push(padded[0]);
+    if (!groupPolygons) return { type: 'FeatureCollection', features };
+    for (const g of groupPolygons.fleetGroups) {
+      if (!g.polygon) continue;
      features.push({
        type: 'Feature',
-        properties: { name: parentName, gearCount: gears.length, inZone: isInZone ? 1 : 0 },
-        geometry: { type: 'Polygon', coordinates: [padded] },
+        properties: { clusterId: Number(g.groupKey), color: g.color },
+        geometry: g.polygon,
      });
    }
    return { type: 'FeatureCollection', features };
-  }, [gearGroupMap, inZoneGearGroups, outZoneGearGroups]);
+  }, [groupPolygons?.fleetGroups]);
+
+  // 2척 선단 라인은 서버에서 Shapely buffer로 이미 Polygon 처리되므로 빈 컬렉션
+  const lineGeoJSON = useMemo((): GeoJSON => ({
+    type: 'FeatureCollection', features: [],
+  }), []);
+
+  // 호버 하이라이트용 단일 폴리곤
+  const hoveredGeoJSON = useMemo((): GeoJSON => {
+    if (hoveredFleetId === null || !groupPolygons) return { type: 'FeatureCollection', features: [] };
+    const g = groupPolygons.fleetGroups.find(f => Number(f.groupKey) === hoveredFleetId);
+    if (!g?.polygon) return { type: 'FeatureCollection', features: [] };
+    return {
+      type: 'FeatureCollection',
+      features: [{
+        type: 'Feature',
+        properties: { clusterId: hoveredFleetId, color: g.color },
+        geometry: g.polygon,
+      }],
+    };
+  }, [hoveredFleetId, groupPolygons?.fleetGroups]);
+
+  // 어구 클러스터 GeoJSON (서버 제공)
+  const gearClusterGeoJson = useMemo((): GeoJSON => {
+    const features: GeoJSON.Feature[] = [];
+    if (!groupPolygons) return { type: 'FeatureCollection', features };
+    for (const g of [...groupPolygons.gearInZoneGroups, ...groupPolygons.gearOutZoneGroups]) {
+      if (!g.polygon) continue;
+      features.push({
+        type: 'Feature',
+        properties: {
+          name: g.groupKey,
+          gearCount: g.memberCount,
+          inZone: g.groupType === 'GEAR_IN_ZONE' ? 1 : 0,
+        },
+        geometry: g.polygon,
+      });
+    }
+    return { type: 'FeatureCollection', features };
+  }, [groupPolygons?.gearInZoneGroups, groupPolygons?.gearOutZoneGroups]);
+
+  // 선단 목록 (멤버 수 내림차순)
+  const fleetList = useMemo(() => {
+    if (!groupPolygons) return [];
+    return groupPolygons.fleetGroups.map(g => ({
+      id: Number(g.groupKey),
+      mmsiList: g.members.map(m => m.mmsi),
+      label: g.groupLabel,
+      memberCount: g.memberCount,
+      areaSqNm: g.areaSqNm,
+      color: g.color,
+      members: g.members,
+    })).sort((a, b) => b.memberCount - a.memberCount);
+  }, [groupPolygons?.fleetGroups]);
+
+  const handleFleetZoom = useCallback((clusterId: number) => {
+    const group = groupPolygons?.fleetGroups.find(g => Number(g.groupKey) === clusterId);
+    if (!group || group.members.length === 0) return;
+    let minLat = Infinity, maxLat = -Infinity, minLng = Infinity, maxLng = -Infinity;
+    for (const m of group.members) {
+      if (m.lat < minLat) minLat = m.lat;
+      if (m.lat > maxLat) maxLat = m.lat;
+      if (m.lon < minLng) minLng = m.lon;
+      if (m.lon > maxLng) maxLng = m.lon;
+    }
+    if (minLat === Infinity) return;
+    onFleetZoom?.({ minLat, maxLat, minLng, maxLng });
+  }, [groupPolygons?.fleetGroups, onFleetZoom]);

  const handleGearGroupZoom = useCallback((parentName: string) => {
    setSelectedGearGroup(prev => prev === parentName ? null : parentName);
@ -354,98 +333,21 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
    requestAnimationFrame(() => {
      document.getElementById(`gear-row-${parentName}`)?.scrollIntoView({ behavior: 'smooth', block: 'start' });
    });
-    const entry = gearGroupMap.get(parentName);
-    if (!entry) return;
-    const all: Ship[] = [...entry.gears];
-    if (entry.parent) all.push(entry.parent);
-    if (all.length === 0) return;
+    const allGroups = groupPolygons
+      ? [...groupPolygons.gearInZoneGroups, ...groupPolygons.gearOutZoneGroups]
+      : [];
+    const group = allGroups.find(g => g.groupKey === parentName);
+    if (!group || group.members.length === 0) return;
    let minLat = Infinity, maxLat = -Infinity, minLng = Infinity, maxLng = -Infinity;
-    for (const s of all) {
-      if (s.lat < minLat) minLat = s.lat;
-      if (s.lat > maxLat) maxLat = s.lat;
-      if (s.lng < minLng) minLng = s.lng;
-      if (s.lng > maxLng) maxLng = s.lng;
+    for (const m of group.members) {
+      if (m.lat < minLat) minLat = m.lat;
+      if (m.lat > maxLat) maxLat = m.lat;
+      if (m.lon < minLng) minLng = m.lon;
+      if (m.lon > maxLng) maxLng = m.lon;
    }
    if (minLat === Infinity) return;
    onFleetZoom?.({ minLat, maxLat, minLng, maxLng });
-  }, [gearGroupMap, onFleetZoom]);
-
-  // GeoJSON 피처 생성
-  const polygonFeatures = useMemo((): ClusterFeature[] => {
-    const features: ClusterFeature[] = [];
-    for (const [clusterId, mmsiList] of clusters) {
-      const points: [number, number][] = [];
-      for (const mmsi of mmsiList) {
-        const ship = shipMap.get(mmsi);
-        if (ship) points.push([ship.lng, ship.lat]);
-      }
-      if (points.length < 2) continue;
-
-      const color = clusterColor(clusterId);
-
-      if (points.length === 2) {
-        features.push({
-          type: 'Feature',
-          id: clusterId,
-          properties: { clusterId, color },
-          geometry: { type: 'LineString', coordinates: points },
-        });
-        continue;
-      }
-
-      const hull = convexHull(points);
-      const padded = padPolygon(hull, 0.02);
-      // 폴리곤 닫기
-      const ring = [...padded, padded[0]];
-      features.push({
-        type: 'Feature',
-        id: clusterId,
-        properties: { clusterId, color },
-        geometry: { type: 'Polygon', coordinates: [ring] },
-      });
-    }
-    return features;
-  }, [clusters, shipMap]);
-
-  const polygonGeoJSON = useMemo((): GeoJSON => ({
-    type: 'FeatureCollection',
-    features: polygonFeatures.filter(f => f.geometry.type === 'Polygon'),
-  }), [polygonFeatures]);
-
-  const lineGeoJSON = useMemo((): GeoJSON => ({
-    type: 'FeatureCollection',
-    features: polygonFeatures.filter(f => f.geometry.type === 'LineString'),
-  }), [polygonFeatures]);
-
-  // 호버 하이라이트용 단일 폴리곤
-  const hoveredGeoJSON = useMemo((): GeoJSON => {
-    if (hoveredFleetId === null) return { type: 'FeatureCollection', features: [] };
-    const f = polygonFeatures.find(p => p.properties.clusterId === hoveredFleetId && p.geometry.type === 'Polygon');
-    if (!f) return { type: 'FeatureCollection', features: [] };
-    return { type: 'FeatureCollection', features: [f] };
-  }, [hoveredFleetId, polygonFeatures]);
-
-  const handleFleetZoom = useCallback((clusterId: number) => {
-    const mmsiList = clusters.get(clusterId) ?? [];
-    if (mmsiList.length === 0) return;
-    let minLat = Infinity, maxLat = -Infinity, minLng = Infinity, maxLng = -Infinity;
-    for (const mmsi of mmsiList) {
-      const ship = shipMap.get(mmsi);
-      if (!ship) continue;
-      if (ship.lat < minLat) minLat = ship.lat;
-      if (ship.lat > maxLat) maxLat = ship.lat;
-      if (ship.lng < minLng) minLng = ship.lng;
-      if (ship.lng > maxLng) maxLng = ship.lng;
-    }
-    if (minLat === Infinity) return;
-    onFleetZoom?.({ minLat, maxLat, minLng, maxLng });
-  }, [clusters, shipMap, onFleetZoom]);
-
-  const fleetList = useMemo(() => {
-    return Array.from(clusters.entries())
-      .map(([id, mmsiList]) => ({ id, mmsiList }))
-      .sort((a, b) => b.mmsiList.length - a.mmsiList.length);
-  }, [clusters]);
+  }, [groupPolygons, onFleetZoom]);

  // 패널 스타일 (AnalysisStatsPanel 패턴)
  const panelStyle: React.CSSProperties = {
@ -492,7 +394,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
  return (
    <>
      {/* 선단 폴리곤 레이어 */}
-      <Source id="fleet-cluster-fill" type="geojson" data={polygonGeoJSON}>
+      <Source id="fleet-cluster-fill" type="geojson" data={fleetPolygonGeoJSON}>
        <Layer
          id="fleet-cluster-fill-layer"
          type="fill"
@ -512,7 +414,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
        />
      </Source>

-      {/* 2척 선단 라인 */}
+      {/* 2척 선단 라인 (서버측 Polygon 처리로 빈 컬렉션) */}
      <Source id="fleet-cluster-line" type="geojson" data={lineGeoJSON}>
        <Layer
          id="fleet-cluster-line-only"
@ -538,27 +440,21 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
        />
      </Source>

-      {/* 선택된 어구 그룹 하이라이트 폴리곤 (deck.gl에서 어구 아이콘 + 모선 마커 표시) */}
+      {/* 선택된 어구 그룹 하이라이트 폴리곤 */}
      {selectedGearGroup && (() => {
-        const entry = gearGroupMap.get(selectedGearGroup);
-        if (!entry) return null;
-        const points: [number, number][] = entry.gears.map(g => [g.lng, g.lat]);
-        if (entry.parent) points.push([entry.parent.lng, entry.parent.lat]);
-
-        const hlFeatures: GeoJSON.Feature[] = [];
-        if (points.length >= 3) {
-          const hull = convexHull(points);
-          const padded = padPolygon(hull, 0.01);
-          padded.push(padded[0]);
-          hlFeatures.push({
+        const allGroups = groupPolygons
+          ? [...groupPolygons.gearInZoneGroups, ...groupPolygons.gearOutZoneGroups]
+          : [];
+        const group = allGroups.find(g => g.groupKey === selectedGearGroup);
+        if (!group?.polygon) return null;
+        const hlGeoJson: GeoJSON.FeatureCollection = {
+          type: 'FeatureCollection',
+          features: [{
            type: 'Feature',
            properties: {},
-            geometry: { type: 'Polygon', coordinates: [padded] },
-          });
-        }
-        if (hlFeatures.length === 0) return null;
-        const hlGeoJson: GeoJSON.FeatureCollection = { type: 'FeatureCollection', features: hlFeatures };
-
+            geometry: group.polygon,
+          }],
+        };
        return (
          <Source id="gear-cluster-selected" type="geojson" data={hlGeoJson}>
            <Layer id="gear-selected-fill" type="fill" paint={{ 'fill-color': '#f97316', 'fill-opacity': 0.25 }} />
@ -592,28 +488,27 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
      {hoverTooltip && (() => {
        if (hoverTooltip.type === 'fleet') {
          const cid = hoverTooltip.id as number;
-          const mmsiList = clusters.get(cid) ?? [];
+          const group = groupPolygons?.fleetGroups.find(g => Number(g.groupKey) === cid);
          const company = companies.get(cid);
-          const gearCount = mmsiList.reduce((acc, mmsi) => acc + (gearsByParent.get(mmsi)?.length ?? 0), 0);
+          const memberCount = group?.memberCount ?? 0;
          return (
            <Popup longitude={hoverTooltip.lng} latitude={hoverTooltip.lat}
              closeButton={false} closeOnClick={false} anchor="bottom"
              className="gl-popup" maxWidth="220px"
            >
              <div style={{ fontFamily: FONT_MONO, fontSize: 10, padding: 4, color: '#e2e8f0' }}>
-                <div style={{ fontWeight: 700, color: clusterColor(cid), marginBottom: 3 }}>
-                  {company?.nameCn || `선단 #${cid}`}
+                <div style={{ fontWeight: 700, color: group?.color ?? '#63b3ed', marginBottom: 3 }}>
+                  {company?.nameCn || group?.groupLabel || `선단 #${cid}`}
                </div>
-                <div style={{ color: '#94a3b8' }}>선박 {mmsiList.length}척 · 어구 {gearCount}개</div>
-                {expandedFleet === cid && mmsiList.slice(0, 5).map(mmsi => {
-                  const s = shipMap.get(mmsi);
-                  const dto = analysisMap.get(mmsi);
-                  const role = dto?.algorithms.fleetRole.role ?? '';
-                  return s ? (
-                    <div key={mmsi} style={{ fontSize: 9, color: '#7ea8c4', marginTop: 2 }}>
-                      {role === 'LEADER' ? '★' : '·'} {s.name || mmsi} <span style={{ color: '#4a6b82' }}>{s.speed?.toFixed(1)}kt</span>
+                <div style={{ color: '#94a3b8' }}>선박 {memberCount}척</div>
+                {expandedFleet === cid && group?.members.slice(0, 5).map(m => {
+                  const dto = analysisMap.get(m.mmsi);
+                  const role = dto?.algorithms.fleetRole.role ?? m.role;
+                  return (
+                    <div key={m.mmsi} style={{ fontSize: 9, color: '#7ea8c4', marginTop: 2 }}>
+                      {role === 'LEADER' ? '★' : '·'} {m.name || m.mmsi} <span style={{ color: '#4a6b82' }}>{m.sog.toFixed(1)}kt</span>
                    </div>
-                  ) : null;
+                  );
                })}
                <div style={{ fontSize: 8, color: '#4a6b82', marginTop: 3 }}>클릭하여 상세 보기</div>
              </div>
@ -622,8 +517,13 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
        }
        if (hoverTooltip.type === 'gear') {
          const name = hoverTooltip.id as string;
-          const entry = gearGroupMap.get(name);
-          if (!entry) return null;
+          const allGroups = groupPolygons
+            ? [...groupPolygons.gearInZoneGroups, ...groupPolygons.gearOutZoneGroups]
+            : [];
+          const group = allGroups.find(g => g.groupKey === name);
+          if (!group) return null;
+          const parentMember = group.members.find(m => m.isParent);
+          const gearMembers = group.members.filter(m => !m.isParent);
          return (
            <Popup longitude={hoverTooltip.lng} latitude={hoverTooltip.lat}
              closeButton={false} closeOnClick={false} anchor="bottom"
@ -631,14 +531,14 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
            >
              <div style={{ fontFamily: FONT_MONO, fontSize: 10, padding: 4, color: '#e2e8f0' }}>
                <div style={{ fontWeight: 700, color: '#f97316', marginBottom: 3 }}>
-                  {name} <span style={{ fontWeight: 400, color: '#94a3b8' }}>어구 {entry.gears.length}개</span>
+                  {name} <span style={{ fontWeight: 400, color: '#94a3b8' }}>어구 {gearMembers.length}개</span>
                </div>
-                {entry.parent && (
-                  <div style={{ fontSize: 9, color: '#fbbf24' }}>모선: {entry.parent.name || entry.parent.mmsi}</div>
+                {parentMember && (
+                  <div style={{ fontSize: 9, color: '#fbbf24' }}>모선: {parentMember.name || parentMember.mmsi}</div>
                )}
-                {selectedGearGroup === name && entry.gears.slice(0, 5).map(g => (
-                  <div key={g.mmsi} style={{ fontSize: 9, color: '#7ea8c4', marginTop: 1 }}>
-                    · {g.name || g.mmsi}
+                {selectedGearGroup === name && gearMembers.slice(0, 5).map(m => (
+                  <div key={m.mmsi} style={{ fontSize: 9, color: '#7ea8c4', marginTop: 1 }}>
+                    · {m.name || m.mmsi}
                  </div>
                ))}
                <div style={{ fontSize: 8, color: '#4a6b82', marginTop: 3 }}>클릭하여 선택/해제</div>
@ -657,7 +557,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
            <span style={{ fontWeight: 700, color: '#63b3ed', letterSpacing: 0.5 }}>
              선단 현황 ({fleetList.length}개)
            </span>
-            <button style={toggleButtonStyle} aria-label="선단 현황 접기/펴기">
+            <button type="button" style={toggleButtonStyle} aria-label="선단 현황 접기/펴기">
              {sectionExpanded.fleet ? '▲' : '▼'}
            </button>
          </div>
@ -668,18 +568,17 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                  선단 데이터 없음
                </div>
              ) : (
-                fleetList.map(({ id, mmsiList }) => {
+                fleetList.map(({ id, mmsiList, label, color, members }) => {
                const company = companies.get(id);
-                const companyName = company?.nameCn ?? `선단 #${id}`;
-                const color = clusterColor(id);
+                const companyName = company?.nameCn ?? label ?? `선단 #${id}`;
                const isOpen = expandedFleet === id;
                const isHovered = hoveredFleetId === id;

-                const mainVessels = mmsiList.filter(mmsi => {
-                  const dto = analysisMap.get(mmsi);
+                const mainMembers = members.filter(m => {
+                  const dto = analysisMap.get(m.mmsi);
                  return dto?.algorithms.fleetRole.role === 'LEADER' || dto?.algorithms.fleetRole.role === 'MEMBER';
                });
-                const gearCount = mmsiList.reduce((acc, mmsi) => acc + (gearsByParent.get(mmsi)?.length ?? 0), 0);
+                const displayMembers = mainMembers.length > 0 ? mainMembers : members;

                return (
                  <div key={id}>
@ -721,7 +620,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                          whiteSpace: 'nowrap',
                          cursor: 'pointer',
                        }}
-                        title={company ? `${company.nameCn} / ${company.nameEn}` : `선단 #${id}`}
+                        title={company ? `${company.nameCn} / ${company.nameEn}` : companyName}
                      >
                        {companyName}
                      </span>
@ -731,6 +630,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                      </span>
                      {/* zoom 버튼 */}
                      <button
+                        type="button"
                        onClick={e => { e.stopPropagation(); handleFleetZoom(id); }}
                        style={{
                          background: 'none',
@ -761,14 +661,13 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                      }}>
                        {/* 선박 목록 */}
                        <div style={{ color: '#64748b', fontSize: 9, marginBottom: 3 }}>선박:</div>
-                        {(mainVessels.length > 0 ? mainVessels : mmsiList).map(mmsi => {
-                          const ship = shipMap.get(mmsi);
-                          const dto = analysisMap.get(mmsi);
-                          const role = dto?.algorithms.fleetRole.role ?? 'MEMBER';
-                          const displayName = ship?.name || mmsi;
+                        {displayMembers.map(m => {
+                          const dto = analysisMap.get(m.mmsi);
+                          const role = dto?.algorithms.fleetRole.role ?? m.role;
+                          const displayName = m.name || m.mmsi;
                          return (
                            <div
-                              key={mmsi}
+                              key={m.mmsi}
                              style={{
                                display: 'flex',
                                alignItems: 'center',
@ -783,7 +682,8 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                                ({role === 'LEADER' ? 'MAIN' : 'SUB'})
                              </span>
                              <button
-                                onClick={() => onShipSelect?.(mmsi)}
+                                type="button"
+                                onClick={() => onShipSelect?.(m.mmsi)}
                                style={{
                                  background: 'none',
                                  border: 'none',
@ -801,20 +701,6 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                            </div>
                          );
                        })}
-
-                        {/* 어구 목록 */}
-                        {gearCount > 0 && (
-                          <>
-                            <div style={{ color: '#64748b', fontSize: 9, marginTop: 4, marginBottom: 2 }}>
-                              어구: {gearCount}개
-                            </div>
-                            {mmsiList.flatMap(mmsi => gearsByParent.get(mmsi) ?? []).map(gear => (
-                              <div key={gear.mmsi} style={{ color: '#475569', fontSize: 9, marginBottom: 1 }}>
-                                {gear.name || gear.mmsi}
-                              </div>
-                            ))}
-                          </>
-                        )}
                      </div>
                    )}
                  </div>
@ -838,9 +724,13 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
              </div>
              {sectionExpanded.inZone && (
                <div style={{ padding: '4px 0' }}>
-                  {inZoneGearGroups.map(({ name, parent, gears, zone }) => {
+                  {inZoneGearGroups.map(g => {
+                    const name = g.groupKey;
                    const isOpen = expandedGearGroup === name;
                    const accentColor = '#dc2626';
+                    const parentMember = g.members.find(m => m.isParent);
+                    const gearMembers = g.members.filter(m => !m.isParent);
+                    const zoneName = g.zoneName ?? '';
                    return (
                      <div key={name} id={`gear-row-${name}`}>
                        <div
@ -850,19 +740,19 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                        >
                          <span onClick={() => setExpandedGearGroup(prev => (prev === name ? null : name))} style={{ color: '#94a3b8', fontSize: 9, flexShrink: 0, cursor: 'pointer' }}>{isOpen ? '▾' : '▸'}</span>
                          <span style={{ width: 8, height: 8, borderRadius: '50%', backgroundColor: accentColor, flexShrink: 0 }} />
-                          <span onClick={() => setExpandedGearGroup(prev => (prev === name ? null : name))} style={{ flex: 1, color: '#e2e8f0', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', cursor: 'pointer' }} title={`${name} — ${zone}`}>{name}</span>
-                          <span style={{ color: '#ef4444', fontSize: 9, flexShrink: 0 }}>{zone}</span>
-                          <span style={{ color: '#64748b', fontSize: 10, flexShrink: 0 }}>({gears.length})</span>
+                          <span onClick={() => setExpandedGearGroup(prev => (prev === name ? null : name))} style={{ flex: 1, color: '#e2e8f0', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', cursor: 'pointer' }} title={`${name} — ${zoneName}`}>{name}</span>
+                          <span style={{ color: '#ef4444', fontSize: 9, flexShrink: 0 }}>{zoneName}</span>
+                          <span style={{ color: '#64748b', fontSize: 10, flexShrink: 0 }}>({gearMembers.length})</span>
                          <button type="button" onClick={e => { e.stopPropagation(); handleGearGroupZoom(name); }} style={{ background: 'none', border: `1px solid rgba(220,38,38,0.5)`, borderRadius: 3, color: accentColor, fontSize: 9, cursor: 'pointer', padding: '1px 4px', flexShrink: 0 }} title="이 어구 그룹으로 지도 이동">zoom</button>
                        </div>
                        {isOpen && (
                          <div style={{ paddingLeft: 24, paddingRight: 10, paddingBottom: 4, fontSize: 9, color: '#94a3b8', borderLeft: `2px solid rgba(220,38,38,0.25)`, marginLeft: 10 }}>
-                            {parent && <div style={{ color: '#fbbf24', marginBottom: 2 }}>모선: {parent.name || parent.mmsi}</div>}
+                            {parentMember && <div style={{ color: '#fbbf24', marginBottom: 2 }}>모선: {parentMember.name || parentMember.mmsi}</div>}
                            <div style={{ color: '#64748b', marginBottom: 2 }}>어구 목록:</div>
-                            {gears.map(g => (
-                              <div key={g.mmsi} style={{ display: 'flex', alignItems: 'center', gap: 4, marginBottom: 1 }}>
-                                <span style={{ flex: 1, color: '#475569', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{g.name || g.mmsi}</span>
-                                <button type="button" onClick={() => onShipSelect?.(g.mmsi)} style={{ background: 'none', border: 'none', color: accentColor, fontSize: 10, cursor: 'pointer', padding: '0 2px', flexShrink: 0 }} title="어구 위치로 이동">▶</button>
+                            {gearMembers.map(m => (
+                              <div key={m.mmsi} style={{ display: 'flex', alignItems: 'center', gap: 4, marginBottom: 1 }}>
+                                <span style={{ flex: 1, color: '#475569', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{m.name || m.mmsi}</span>
+                                <button type="button" onClick={() => onShipSelect?.(m.mmsi)} style={{ background: 'none', border: 'none', color: accentColor, fontSize: 10, cursor: 'pointer', padding: '0 2px', flexShrink: 0 }} title="어구 위치로 이동">▶</button>
                              </div>
                            ))}
                          </div>
@ -882,14 +772,17 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                <span style={{ fontWeight: 700, color: '#f97316', letterSpacing: 0.3 }}>
                  비허가 어구 ({outZoneGearGroups.length}개)
                </span>
-                <button style={toggleButtonStyle} aria-label="비허가 어구 접기/펴기">
+                <button type="button" style={toggleButtonStyle} aria-label="비허가 어구 접기/펴기">
                  {sectionExpanded.outZone ? '▲' : '▼'}
                </button>
              </div>
              {sectionExpanded.outZone && (
                <div style={{ padding: '4px 0' }}>
-                  {outZoneGearGroups.map(({ name, parent, gears }) => {
+                  {outZoneGearGroups.map(g => {
+                  const name = g.groupKey;
                  const isOpen = expandedGearGroup === name;
+                  const parentMember = g.members.find(m => m.isParent);
+                  const gearMembers = g.members.filter(m => !m.isParent);
                  return (
                    <div key={name} id={`gear-row-${name}`}>
                      <div
@ -930,7 +823,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                          {name}
                        </span>
                        <span style={{ color: '#64748b', fontSize: 10, flexShrink: 0 }}>
-                          ({gears.length}개)
+                          ({gearMembers.length}개)
                        </span>
                        <button
                          type="button"
@ -961,25 +854,25 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                          borderLeft: '2px solid rgba(249,115,22,0.2)',
                          marginLeft: 10,
                        }}>
-                          {parent && (
+                          {parentMember && (
                            <div style={{ color: '#fbbf24', marginBottom: 2 }}>
-                              모선: {parent.name || parent.mmsi}
+                              모선: {parentMember.name || parentMember.mmsi}
                            </div>
            )}
                          <div style={{ color: '#64748b', marginBottom: 2 }}>어구 목록:</div>
-                          {gears.map(g => (
-                            <div key={g.mmsi} style={{
+                          {gearMembers.map(m => (
+                            <div key={m.mmsi} style={{
                              display: 'flex',
                              alignItems: 'center',
                              gap: 4,
                              marginBottom: 1,
                            }}>
                              <span style={{ flex: 1, color: '#475569', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>
-                                {g.name || g.mmsi}
+                                {m.name || m.mmsi}
                              </span>
                              <button
                                type="button"
-                                onClick={() => onShipSelect?.(g.mmsi)}
+                                onClick={() => onShipSelect?.(m.mmsi)}
                                style={{
                                  background: 'none',
                                  border: 'none',
@ -990,7 +883,7 @@ export function FleetClusterLayer({ ships, analysisMap: analysisMapProp, cluster
                                  flexShrink: 0,
                                }}
                                title="어구 위치로 이동"
-                                aria-label={`${g.name || g.mmsi} 위치로 이동`}
+                                aria-label={`${m.name || m.mmsi} 위치로 이동`}
                              >
                                ▶
                              </button>
--- a/frontend/src/components/korea/KoreaDashboard.tsx
+++ b/frontend/src/components/korea/KoreaDashboard.tsx
@ -11,6 +11,7 @@ import { ReplayControls } from '../common/ReplayControls';
 import { TimelineSlider } from '../common/TimelineSlider';
 import { useKoreaData } from '../../hooks/useKoreaData';
 import { useVesselAnalysis } from '../../hooks/useVesselAnalysis';
+import { useGroupPolygons } from '../../hooks/useGroupPolygons';
 import { useKoreaFilters } from '../../hooks/useKoreaFilters';
 import { useSharedFilters } from '../../hooks/useSharedFilters';
 import { EAST_ASIA_PORTS } from '../../data/ports';
@ -161,6 +162,7 @@ export const KoreaDashboard = ({
  });

  const vesselAnalysis = useVesselAnalysis(true);
+  const groupPolygons = useGroupPolygons(true);

  const koreaFiltersResult = useKoreaFilters(
    koreaData.ships,
@ -259,12 +261,10 @@ export const KoreaDashboard = ({
    <>
      {headerSlot && createPortal(
        <div className="mode-toggle">
-          {/* 불법어선 탭 — 준비 중, 임시 숨김
          <button type="button" className={`mode-btn ${koreaFiltersResult.filters.illegalFishing ? 'active live' : ''}`}
            onClick={() => koreaFiltersResult.setFilter('illegalFishing', !koreaFiltersResult.filters.illegalFishing)} title={t('filters.illegalFishing')}>
            <span className="text-[11px]">🚫🐟</span>{t('filters.illegalFishing')}
          </button>
-          */}
          <button type="button" className={`mode-btn ${koreaFiltersResult.filters.illegalTransship ? 'active live' : ''}`}
            onClick={() => koreaFiltersResult.setFilter('illegalTransship', !koreaFiltersResult.filters.illegalTransship)} title={t('filters.illegalTransship')}>
            <span className="text-[11px]">⚓</span>{t('filters.illegalTransship')}
@ -329,6 +329,7 @@ export const KoreaDashboard = ({
            cnFishingSuspects={koreaFiltersResult.cnFishingSuspects}
            dokdoAlerts={koreaFiltersResult.dokdoAlerts}
            vesselAnalysis={vesselAnalysis}
+            groupPolygons={groupPolygons}
            hiddenShipCategories={hiddenShipCategories}
            hiddenNationalities={hiddenNationalities}
          />
--- a/frontend/src/components/korea/KoreaMap.tsx
+++ b/frontend/src/components/korea/KoreaMap.tsx
@ -36,6 +36,7 @@ import type { PowerFacility } from '../../services/infra';
 import type { Ship, Aircraft, SatellitePosition } from '../../types';
 import type { OsintItem } from '../../services/osint';
 import type { UseVesselAnalysisResult } from '../../hooks/useVesselAnalysis';
+import type { UseGroupPolygonsResult } from '../../hooks/useGroupPolygons';
 import { countryLabelsGeoJSON } from '../../data/countryLabels';
 import { useLocalStorage } from '../../hooks/useLocalStorage';
 import 'maplibre-gl/dist/maplibre-gl.css';
@ -65,6 +66,7 @@ interface Props {
  cnFishingSuspects: Set<string>;
  dokdoAlerts: { mmsi: string; name: string; dist: number; time: number }[];
  vesselAnalysis?: UseVesselAnalysisResult;
+  groupPolygons?: UseGroupPolygonsResult;
  hiddenShipCategories?: Set<string>;
  hiddenNationalities?: Set<string>;
 }
@ -142,7 +144,7 @@ const FILTER_I18N_KEY: Record<string, string> = {
  cnFishing: 'filters.cnFishingMonitor',
 };

-export function KoreaMap({ ships, allShips, aircraft, satellites, layers, osintFeed, currentTime, koreaFilters, transshipSuspects, cableWatchSuspects, dokdoWatchSuspects, dokdoAlerts, vesselAnalysis, hiddenShipCategories, hiddenNationalities }: Props) {
+export function KoreaMap({ ships, allShips, aircraft, satellites, layers, osintFeed, currentTime, koreaFilters, transshipSuspects, cableWatchSuspects, dokdoWatchSuspects, dokdoAlerts, vesselAnalysis, groupPolygons, hiddenShipCategories, hiddenNationalities }: Props) {
  const { t } = useTranslation();
  const mapRef = useRef<MapRef>(null);
  const [infra, setInfra] = useState<PowerFacility[]>([]);
@ -661,6 +663,7 @@ export function KoreaMap({ ships, allShips, aircraft, satellites, layers, osintF
          ships={allShips ?? ships}
          analysisMap={vesselAnalysis ? vesselAnalysis.analysisMap : undefined}
          clusters={vesselAnalysis ? vesselAnalysis.clusters : undefined}
+          groupPolygons={groupPolygons}
          onShipSelect={handleAnalysisShipSelect}
          onFleetZoom={handleFleetZoom}
          onSelectedGearChange={setSelectedGearData}
--- a/frontend/src/hooks/useGroupPolygons.ts
+++ b/frontend/src/hooks/useGroupPolygons.ts
@ -0,0 +1,69 @@
+import { useState, useEffect, useRef, useMemo, useCallback } from 'react';
+import { fetchGroupPolygons } from '../services/vesselAnalysis';
+import type { GroupPolygonDto } from '../services/vesselAnalysis';
+
+const POLL_INTERVAL_MS = 5 * 60_000; // 5분
+
+export interface UseGroupPolygonsResult {
+  fleetGroups: GroupPolygonDto[];
+  gearInZoneGroups: GroupPolygonDto[];
+  gearOutZoneGroups: GroupPolygonDto[];
+  allGroups: GroupPolygonDto[];
+  isLoading: boolean;
+  lastUpdated: number;
+}
+
+const EMPTY: UseGroupPolygonsResult = {
+  fleetGroups: [],
+  gearInZoneGroups: [],
+  gearOutZoneGroups: [],
+  allGroups: [],
+  isLoading: false,
+  lastUpdated: 0,
+};
+
+export function useGroupPolygons(enabled: boolean): UseGroupPolygonsResult {
+  const [allGroups, setAllGroups] = useState<GroupPolygonDto[]>([]);
+  const [isLoading, setIsLoading] = useState(false);
+  const [lastUpdated, setLastUpdated] = useState(0);
+  const timerRef = useRef<ReturnType<typeof setInterval>>();
+
+  const load = useCallback(async () => {
+    setIsLoading(true);
+    try {
+      const groups = await fetchGroupPolygons();
+      setAllGroups(groups);
+      setLastUpdated(Date.now());
+    } catch {
+      // 네트워크 오류 시 기존 데이터 유지
+    } finally {
+      setIsLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    if (!enabled) return;
+    load();
+    timerRef.current = setInterval(load, POLL_INTERVAL_MS);
+    return () => clearInterval(timerRef.current);
+  }, [enabled, load]);
+
+  const fleetGroups = useMemo(
+    () => allGroups.filter(g => g.groupType === 'FLEET'),
+    [allGroups],
+  );
+
+  const gearInZoneGroups = useMemo(
+    () => allGroups.filter(g => g.groupType === 'GEAR_IN_ZONE'),
+    [allGroups],
+  );
+
+  const gearOutZoneGroups = useMemo(
+    () => allGroups.filter(g => g.groupType === 'GEAR_OUT_ZONE'),
+    [allGroups],
+  );
+
+  if (!enabled) return EMPTY;
+
+  return { fleetGroups, gearInZoneGroups, gearOutZoneGroups, allGroups, isLoading, lastUpdated };
+}
--- a/frontend/src/services/vesselAnalysis.ts
+++ b/frontend/src/services/vesselAnalysis.ts
@ -17,6 +17,58 @@ export interface FleetCompany {
  nameEn: string;
 }

+/* ── Group Polygon Types ─────────────────────────────────────── */
+
+export interface MemberInfo {
+  mmsi: string;
+  name: string;
+  lat: number;
+  lon: number;
+  sog: number;
+  cog: number;
+  role: string;
+  isParent: boolean;
+}
+
+export interface GroupPolygonDto {
+  groupType: 'FLEET' | 'GEAR_IN_ZONE' | 'GEAR_OUT_ZONE';
+  groupKey: string;
+  groupLabel: string;
+  snapshotTime: string;
+  polygon: GeoJSON.Polygon | null;
+  centerLat: number;
+  centerLon: number;
+  areaSqNm: number;
+  memberCount: number;
+  zoneId: string | null;
+  zoneName: string | null;
+  members: MemberInfo[];
+  color: string;
+}
+
+export async function fetchGroupPolygons(): Promise<GroupPolygonDto[]> {
+  const res = await fetch(`${API_BASE}/vessel-analysis/groups`, {
+    headers: { accept: 'application/json' },
+  });
+  if (!res.ok) return [];
+  const data: { count: number; items: GroupPolygonDto[] } = await res.json();
+  return data.items ?? [];
+}
+
+export async function fetchGroupDetail(groupKey: string): Promise<GroupPolygonDto | null> {
+  const res = await fetch(`${API_BASE}/vessel-analysis/groups/${encodeURIComponent(groupKey)}/detail`);
+  if (!res.ok) return null;
+  return res.json();
+}
+
+export async function fetchGroupHistory(groupKey: string, hours = 24): Promise<GroupPolygonDto[]> {
+  const res = await fetch(`${API_BASE}/vessel-analysis/groups/${encodeURIComponent(groupKey)}/history?hours=${hours}`);
+  if (!res.ok) return [];
+  return res.json();
+}
+
+/* ── Fleet Companies ─────────────────────────────────────────── */
+
 // 캐시 (세션 중 1회 로드)
 let companyCache: Map<number, FleetCompany> | null = null;

--- a/prediction/algorithms/polygon_builder.py
+++ b/prediction/algorithms/polygon_builder.py
@ -0,0 +1,422 @@
+"""선단/어구그룹 폴리곤 생성기.
+
+프론트엔드 FleetClusterLayer.tsx의 어구그룹 탐지 + convexHull/padPolygon 로직을
+Python으로 이관한다. Shapely 라이브러리로 폴리곤 생성.
+"""
+
+from __future__ import annotations
+
+import logging
+import math
+import re
+from datetime import datetime, timezone
+from typing import Optional
+
+try:
+    from shapely.geometry import MultiPoint, Point
+    from shapely import wkt as shapely_wkt
+    _SHAPELY_AVAILABLE = True
+except ImportError:
+    _SHAPELY_AVAILABLE = False
+
+from algorithms.location import classify_zone
+
+logger = logging.getLogger(__name__)
+
+# 프론트 FleetClusterLayer.tsx gearGroupMap 패턴과 동일
+GEAR_PATTERN = re.compile(r'^(.+?)_\d+_\d+_?$')
+MAX_DIST_DEG = 0.15         # ~10NM
+STALE_SEC = 3600            # 60분
+FLEET_BUFFER_DEG = 0.02
+GEAR_BUFFER_DEG = 0.01
+MIN_GEAR_GROUP_SIZE = 2     # 최소 어구 수 (비허가 구역 외)
+
+# 수역 내 어구 색상, 수역 외 어구 색상
+_COLOR_GEAR_IN_ZONE = '#ef4444'
+_COLOR_GEAR_OUT_ZONE = '#f97316'
+
+# classify_zone이 수역 내로 판정하는 zone 값 목록
+_IN_ZONE_PREFIXES = ('ZONE_',)
+
+
+def _is_in_zone(zone_info: dict) -> bool:
+    """classify_zone 결과가 특정어업수역 내인지 판별."""
+    zone = zone_info.get('zone', '')
+    return any(zone.startswith(prefix) for prefix in _IN_ZONE_PREFIXES)
+
+
+def _cluster_color(seed: int) -> str:
+    """프론트 clusterColor(id) 이관 — hsl({(seed * 137) % 360}, 80%, 55%)."""
+    h = (seed * 137) % 360
+    return f'hsl({h}, 80%, 55%)'
+
+
+def compute_area_sq_nm(polygon, center_lat: float) -> float:
+    """Shapely Polygon의 면적(degrees²) → 제곱 해리 변환.
+
+    1도 위도 ≈ 60 NM, 1도 경도 ≈ 60 * cos(lat) NM
+    sq_nm = area_deg2 * 60 * 60 * cos(center_lat_rad)
+    """
+    area_deg2 = polygon.area
+    center_lat_rad = math.radians(center_lat)
+    sq_nm = area_deg2 * 60.0 * 60.0 * math.cos(center_lat_rad)
+    return round(sq_nm, 4)
+
+
+def build_group_polygon(
+    points: list[tuple[float, float]],
+    buffer_deg: float,
+) -> tuple[Optional[str], Optional[str], float, float, float]:
+    """좌표 목록으로 버퍼 폴리곤을 생성한다.
+
+    Args:
+        points: (lon, lat) 좌표 목록 — Shapely (x, y) 순서.
+        buffer_deg: 버퍼 크기(도).
+
+    Returns:
+        (polygon_wkt, center_wkt, area_sq_nm, center_lat, center_lon)
+        — polygon_wkt/center_wkt: ST_GeomFromText에 사용할 WKT 문자열.
+        — 좌표가 없거나 Shapely 미설치 시 (None, None, 0.0, 0.0, 0.0).
+    """
+    if not _SHAPELY_AVAILABLE:
+        logger.warning('shapely 미설치 — build_group_polygon 건너뜀')
+        return None, None, 0.0, 0.0, 0.0
+
+    if not points:
+        return None, None, 0.0, 0.0, 0.0
+
+    if len(points) == 1:
+        geom = Point(points[0]).buffer(buffer_deg)
+    elif len(points) == 2:
+        # LineString → buffer로 Polygon 생성
+        from shapely.geometry import LineString
+        geom = LineString(points).buffer(buffer_deg)
+    else:
+        # 3점 이상 → convex_hull → buffer
+        geom = MultiPoint(points).convex_hull.buffer(buffer_deg)
+
+    # 중심 계산
+    centroid = geom.centroid
+    center_lon = centroid.x
+    center_lat = centroid.y
+
+    area_sq_nm = compute_area_sq_nm(geom, center_lat)
+    polygon_wkt = shapely_wkt.dumps(geom, rounding_precision=6)
+    center_wkt = f'POINT({center_lon:.6f} {center_lat:.6f})'
+
+    return polygon_wkt, center_wkt, area_sq_nm, center_lat, center_lon
+
+
+def detect_gear_groups(
+    vessel_dfs: dict,
+    vessel_store,
+    now: Optional[datetime] = None,
+) -> list[dict]:
+    """어구 이름 패턴으로 어구그룹을 탐지한다.
+
+    프론트엔드 FleetClusterLayer.tsx gearGroupMap useMemo 로직 이관.
+
+    Args:
+        vessel_dfs: {mmsi: DataFrame} — 각 DataFrame은 lat, lon, sog, cog, timestamp 칼럼.
+        vessel_store: VesselStore — get_vessel_info(mmsi) → {name, ...}.
+        now: 기준 시각 (None이면 UTC now).
+
+    Returns:
+        [{parent_name, parent_mmsi, members: [{mmsi, name, lat, lon, sog, cog}]}]
+    """
+    if now is None:
+        now = datetime.now(timezone.utc)
+
+    # 선박명 → mmsi 맵 (모선 탐색용)
+    name_to_mmsi: dict[str, str] = {}
+    for mmsi, df in vessel_dfs.items():
+        if df is None or len(df) == 0:
+            continue
+        info = vessel_store.get_vessel_info(mmsi)
+        name: str = (info or {}).get('name', '') or ''
+        name = name.strip()
+        if name and not GEAR_PATTERN.match(name):
+            name_to_mmsi[name] = mmsi
+
+    # 1단계: 같은 모선명 어구 수집 (60분 이내만)
+    raw_groups: dict[str, list[dict]] = {}
+    for mmsi, df in vessel_dfs.items():
+        if df is None or len(df) == 0:
+            continue
+        last = df.iloc[-1]
+        ts = last.get('timestamp') if hasattr(last, 'get') else last['timestamp']
+
+        # timestamp → datetime 변환
+        if isinstance(ts, datetime):
+            last_dt = ts if ts.tzinfo is not None else ts.replace(tzinfo=timezone.utc)
+        else:
+            # pandas Timestamp 또는 숫자(unix seconds)
+            try:
+                import pandas as pd
+                last_dt = pd.Timestamp(ts).to_pydatetime()
+                if last_dt.tzinfo is None:
+                    last_dt = last_dt.replace(tzinfo=timezone.utc)
+            except Exception:
+                continue
+
+        age_sec = (now - last_dt).total_seconds()
+        if age_sec > STALE_SEC:
+            continue
+
+        info = vessel_store.get_vessel_info(mmsi)
+        name = (info or {}).get('name', '') or ''
+        name = name.strip()
+
+        m = GEAR_PATTERN.match(name)
+        if not m:
+            continue
+
+        parent_name = m.group(1).strip()
+        entry = {
+            'mmsi': mmsi,
+            'name': name,
+            'lat': float(last['lat']),
+            'lon': float(last['lon']),
+            'sog': float(last.get('sog', 0) if hasattr(last, 'get') else last['sog']),
+            'cog': float(last.get('cog', 0) if hasattr(last, 'get') else last['cog']),
+        }
+        raw_groups.setdefault(parent_name, []).append(entry)
+
+    # 2단계: 거리 기반 서브 클러스터링 (anchor 기준 MAX_DIST_DEG 이내만)
+    results: list[dict] = []
+    for parent_name, gears in raw_groups.items():
+        parent_mmsi = name_to_mmsi.get(parent_name)
+
+        # 기준점(anchor): 모선 있으면 모선 위치, 없으면 첫 어구
+        anchor_lat: Optional[float] = None
+        anchor_lon: Optional[float] = None
+
+        if parent_mmsi and parent_mmsi in vessel_dfs:
+            parent_df = vessel_dfs[parent_mmsi]
+            if parent_df is not None and len(parent_df) > 0:
+                parent_last = parent_df.iloc[-1]
+                anchor_lat = float(parent_last['lat'])
+                anchor_lon = float(parent_last['lon'])
+
+        if anchor_lat is None and gears:
+            anchor_lat = gears[0]['lat']
+            anchor_lon = gears[0]['lon']
+
+        if anchor_lat is None or anchor_lon is None:
+            continue
+
+        # MAX_DIST_DEG 이내 어구만 포함
+        _anchor_lat: float = anchor_lat
+        _anchor_lon: float = anchor_lon
+        nearby = [
+            g for g in gears
+            if abs(g['lat'] - _anchor_lat) <= MAX_DIST_DEG
+            and abs(g['lon'] - _anchor_lon) <= MAX_DIST_DEG
+        ]
+
+        if not nearby:
+            continue
+
+        # members 구성: 어구 목록
+        members = [
+            {
+                'mmsi': g['mmsi'],
+                'name': g['name'],
+                'lat': g['lat'],
+                'lon': g['lon'],
+                'sog': g['sog'],
+                'cog': g['cog'],
+            }
+            for g in nearby
+        ]
+
+        results.append({
+            'parent_name': parent_name,
+            'parent_mmsi': parent_mmsi,
+            'members': members,
+        })
+
+    return results
+
+
+def build_all_group_snapshots(
+    vessel_dfs: dict,
+    vessel_store,
+    company_vessels: dict[int, list[str]],
+    companies: dict[int, dict],
+) -> list[dict]:
+    """선단(FLEET) + 어구그룹(GEAR) 폴리곤 스냅샷을 생성한다.
+
+    Shapely 미설치 시 빈 리스트를 반환한다.
+
+    Args:
+        vessel_dfs: {mmsi: DataFrame}.
+        vessel_store: VesselStore — get_vessel_info(mmsi).
+        company_vessels: {company_id: [mmsi_list]}.
+        companies: {id: {name_cn, name_en}}.
+
+    Returns:
+        DB INSERT용 dict 목록.
+    """
+    if not _SHAPELY_AVAILABLE:
+        logger.warning('shapely 미설치 — build_all_group_snapshots 빈 리스트 반환')
+        return []
+
+    now = datetime.now(timezone.utc)
+    snapshots: list[dict] = []
+
+    # ── FLEET 타입: company_vessels 순회 ──────────────────────────
+    for company_id, mmsi_list in company_vessels.items():
+        company_info = companies.get(company_id, {})
+        group_label = company_info.get('name_cn') or company_info.get('name_en') or str(company_id)
+
+        # 각 선박의 최신 좌표 추출
+        points: list[tuple[float, float]] = []
+        members: list[dict] = []
+
+        for mmsi in mmsi_list:
+            df = vessel_dfs.get(mmsi)
+            if df is None or len(df) == 0:
+                continue
+            last = df.iloc[-1]
+            lat = float(last['lat'])
+            lon = float(last['lon'])
+            sog_val = last.get('sog', 0) if hasattr(last, 'get') else last['sog']
+            cog_val = last.get('cog', 0) if hasattr(last, 'get') else last['cog']
+            sog = float(sog_val)
+            cog = float(cog_val)
+            points.append((lon, lat))
+            members.append({
+                'mmsi': mmsi,
+                'name': (vessel_store.get_vessel_info(mmsi) or {}).get('name', ''),
+                'lat': lat,
+                'lon': lon,
+                'sog': sog,
+                'cog': cog,
+                'role': 'LEADER' if mmsi == mmsi_list[0] else 'MEMBER',
+                'isParent': False,
+            })
+
+        # 2척 미만은 폴리곤 미생성
+        if len(points) < 2:
+            continue
+
+        polygon_wkt, center_wkt, area_sq_nm, center_lat, center_lon = build_group_polygon(
+            points, FLEET_BUFFER_DEG
+        )
+
+        snapshots.append({
+            'group_type': 'FLEET',
+            'group_key': str(company_id),
+            'group_label': group_label,
+            'snapshot_time': now,
+            'polygon_wkt': polygon_wkt,
+            'center_wkt': center_wkt,
+            'area_sq_nm': area_sq_nm,
+            'member_count': len(members),
+            'zone_id': None,
+            'zone_name': None,
+            'members': members,
+            'color': _cluster_color(company_id),
+        })
+
+    # ── GEAR 타입: detect_gear_groups 결과 순회 ───────────────────
+    gear_groups = detect_gear_groups(vessel_dfs, vessel_store, now=now)
+
+    for group in gear_groups:
+        parent_name: str = group['parent_name']
+        parent_mmsi: Optional[str] = group['parent_mmsi']
+        gear_members: list[dict] = group['members']
+
+        # 수역 분류: anchor(모선 or 첫 어구) 위치 기준
+        anchor_lat: Optional[float] = None
+        anchor_lon: Optional[float] = None
+
+        if parent_mmsi and parent_mmsi in vessel_dfs:
+            parent_df = vessel_dfs.get(parent_mmsi)
+            if parent_df is not None and len(parent_df) > 0:
+                p_last = parent_df.iloc[-1]
+                anchor_lat = float(p_last['lat'])
+                anchor_lon = float(p_last['lon'])
+
+        if anchor_lat is None and gear_members:
+            anchor_lat = gear_members[0]['lat']
+            anchor_lon = gear_members[0]['lon']
+
+        if anchor_lat is None:
+            continue
+
+        zone_info = classify_zone(float(anchor_lat), float(anchor_lon))
+        in_zone = _is_in_zone(zone_info)
+        zone_id = zone_info.get('zone') if in_zone else None
+        zone_name = zone_info.get('zone_name') if in_zone else None
+
+        # 비허가(수역 외) 어구: MIN_GEAR_GROUP_SIZE 미만 제외
+        if not in_zone and len(gear_members) < MIN_GEAR_GROUP_SIZE:
+            continue
+
+        # 폴리곤 points: 어구 좌표 + 모선 좌표
+        points = [(g['lon'], g['lat']) for g in gear_members]
+        if parent_mmsi and parent_mmsi in vessel_dfs:
+            parent_df = vessel_dfs.get(parent_mmsi)
+            if parent_df is not None and len(parent_df) > 0:
+                p_last = parent_df.iloc[-1]
+                p_lat = float(p_last['lat'])
+                p_lon = float(p_last['lon'])
+                if (p_lon, p_lat) not in points:
+                    points.append((p_lon, p_lat))
+
+        polygon_wkt, center_wkt, area_sq_nm, _clat, _clon = build_group_polygon(
+            points, GEAR_BUFFER_DEG
+        )
+
+        # members JSONB 구성
+        members_out: list[dict] = []
+        # 모선 먼저
+        if parent_mmsi and parent_mmsi in vessel_dfs:
+            parent_df = vessel_dfs.get(parent_mmsi)
+            if parent_df is not None and len(parent_df) > 0:
+                p_last = parent_df.iloc[-1]
+                p_sog = float(p_last.get('sog', 0) if hasattr(p_last, 'get') else p_last['sog'])
+                p_cog = float(p_last.get('cog', 0) if hasattr(p_last, 'get') else p_last['cog'])
+                members_out.append({
+                    'mmsi': parent_mmsi,
+                    'name': parent_name,
+                    'lat': float(p_last['lat']),
+                    'lon': float(p_last['lon']),
+                    'sog': p_sog,
+                    'cog': p_cog,
+                    'role': 'PARENT',
+                    'isParent': True,
+                })
+        # 어구 목록
+        for g in gear_members:
+            members_out.append({
+                'mmsi': g['mmsi'],
+                'name': g['name'],
+                'lat': g['lat'],
+                'lon': g['lon'],
+                'sog': g['sog'],
+                'cog': g['cog'],
+                'role': 'GEAR',
+                'isParent': False,
+            })
+
+        color = _COLOR_GEAR_IN_ZONE if in_zone else _COLOR_GEAR_OUT_ZONE
+
+        snapshots.append({
+            'group_type': 'GEAR_IN_ZONE' if in_zone else 'GEAR_OUT_ZONE',
+            'group_key': parent_name,
+            'group_label': parent_name,
+            'snapshot_time': now,
+            'polygon_wkt': polygon_wkt,
+            'center_wkt': center_wkt,
+            'area_sq_nm': area_sq_nm,
+            'member_count': len(members_out),
+            'zone_id': zone_id,
+            'zone_name': zone_name,
+            'members': members_out,
+            'color': color,
+        })
+
+    return snapshots
--- a/prediction/db/kcgdb.py
+++ b/prediction/db/kcgdb.py
@ -1,3 +1,4 @@
+import json
 import logging
 from contextlib import contextmanager
 from typing import TYPE_CHECKING, Optional
@ -137,3 +138,76 @@ def cleanup_old(hours: int = 48) -> int:
    except Exception as e:
        logger.error('failed to cleanup old results: %s', e)
        return 0
+
+
+def save_group_snapshots(snapshots: list[dict]) -> int:
+    """group_polygon_snapshots에 폴리곤 스냅샷 배치 INSERT.
+
+    snapshots: polygon_builder.build_all_group_snapshots() 결과
+    각 항목은: group_type, group_key, group_label, snapshot_time,
+              polygon_wkt (str|None), center_wkt (str|None),
+              area_sq_nm, member_count, zone_id, zone_name,
+              members (list[dict]), color
+    """
+    if not snapshots:
+        return 0
+
+    insert_sql = """
+        INSERT INTO kcg.group_polygon_snapshots (
+            group_type, group_key, group_label, snapshot_time,
+            polygon, center_point, area_sq_nm, member_count,
+            zone_id, zone_name, members, color
+        ) VALUES (
+            %s, %s, %s, %s,
+            ST_GeomFromText(%s, 4326), ST_GeomFromText(%s, 4326),
+            %s, %s, %s, %s, %s::jsonb, %s
+        )
+    """
+
+    inserted = 0
+    try:
+        with get_conn() as conn:
+            with conn.cursor() as cur:
+                for s in snapshots:
+                    cur.execute(
+                        insert_sql,
+                        (
+                            s['group_type'],
+                            s['group_key'],
+                            s['group_label'],
+                            s['snapshot_time'],
+                            s.get('polygon_wkt'),
+                            s.get('center_wkt'),
+                            s.get('area_sq_nm'),
+                            s.get('member_count'),
+                            s.get('zone_id'),
+                            s.get('zone_name'),
+                            json.dumps(s.get('members', []), ensure_ascii=False),
+                            s.get('color'),
+                        ),
+                    )
+                    inserted += 1
+                conn.commit()
+        logger.info('saved %d group polygon snapshots', inserted)
+        return inserted
+    except Exception as e:
+        logger.error('failed to save group snapshots: %s', e)
+        return 0
+
+
+def cleanup_group_snapshots(days: int = 7) -> int:
+    """오래된 그룹 폴리곤 스냅샷 삭제."""
+    try:
+        with get_conn() as conn:
+            with conn.cursor() as cur:
+                cur.execute(
+                    f"DELETE FROM kcg.group_polygon_snapshots WHERE snapshot_time < NOW() - INTERVAL '{days} days'",
+                )
+                deleted = cur.rowcount
+                conn.commit()
+        if deleted > 0:
+            logger.info('cleaned up %d old group snapshots (older than %dd)', deleted, days)
+        return deleted
+    except Exception as e:
+        logger.error('failed to cleanup group snapshots: %s', e)
+        return 0
--- a/prediction/fleet_tracker.py
+++ b/prediction/fleet_tracker.py
@ -317,6 +317,19 @@ class FleetTracker:
        cur.close()
        logger.info('fleet snapshot saved: %d companies', len(company_vessels))

+    def get_company_vessels(self, vessel_dfs: dict[str, 'pd.DataFrame']) -> dict[int, list[str]]:
+        """현재 AIS 수신 중인 등록 선단의 회사별 MMSI 목록 반환.
+
+        Returns: {company_id: [mmsi, ...]}
+        """
+        result: dict[int, list[str]] = {}
+        for mmsi, vid in self._mmsi_to_vid.items():
+            v = self._vessels.get(vid)
+            if not v or mmsi not in vessel_dfs:
+                continue
+            result.setdefault(v['company_id'], []).append(mmsi)
+        return result
+

 # 싱글턴
 fleet_tracker = FleetTracker()
--- a/prediction/requirements.txt
+++ b/prediction/requirements.txt
@ -6,3 +6,4 @@ numpy>=1.26
 pandas>=2.2
 scikit-learn>=1.5
 apscheduler>=3.10
+shapely>=2.0
--- a/prediction/scheduler.py
+++ b/prediction/scheduler.py
@ -99,6 +99,23 @@ def run_analysis_cycle():

            fleet_tracker.save_snapshot(vessel_dfs, kcg_conn)

+            # 4.5 그룹 폴리곤 생성 + 저장
+            try:
+                from algorithms.polygon_builder import detect_gear_groups, build_all_group_snapshots
+
+                company_vessels = fleet_tracker.get_company_vessels(vessel_dfs)
+                gear_groups = detect_gear_groups(vessel_dfs, vessel_store)
+                group_snapshots = build_all_group_snapshots(
+                    vessel_dfs, vessel_store, company_vessels,
+                    fleet_tracker._companies,
+                )
+                saved = kcgdb.save_group_snapshots(group_snapshots)
+                cleaned = kcgdb.cleanup_group_snapshots(days=7)
+                logger.info('group polygons: %d saved, %d cleaned, %d gear groups',
+                            saved, cleaned, len(gear_groups))
+            except Exception as e:
+                logger.warning('group polygon generation failed: %s', e)
+
        # 5. 선박별 추가 알고리즘 → AnalysisResult 생성
        results = []
        for c in classifications: