fix(map): group collocated user markers

apps/web/src/app/globals.css

@@ -74,6 +74,19 @@ svg a:focus .map-marker {
   opacity: 1;
 }
 
+.map-user-cluster {
+  display: grid !important;
+  place-items: center;
+  border: 3px solid var(--panel);
+  border-radius: 999px;
+  background: var(--accent);
+  color: var(--panel);
+  font-family: var(--font-mono);
+  font-size: 0.75rem;
+  font-weight: 700;
+  box-shadow: 0 0 0 1px var(--ink);
+}
+
 ::selection {
   background: var(--accent);
   color: var(--panel);

apps/web/src/components/map-view-toggle.tsx

@@ -2,6 +2,7 @@
 
 import type { ReactNode } from "react";
 import { useEffect, useRef, useState } from "react";
+import { groupMapLocations } from "@/lib/user-location-map";
 import type { UserMapLocation } from "./user-world-map";
 
 export function MapViewToggle({ locations, children }: { locations: UserMapLocation[]; children: ReactNode }) {
@@ -40,33 +41,76 @@ function InteractiveMap({ locations }: { locations: UserMapLocation[] }) {
       }).addTo(map);
 
       const bounds: [number, number][] = [];
-      for (const user of locations) {
-        const marker = leaflet.circleMarker([user.latitude, user.longitude], {
-          radius: 8,
-          color: "#eee8d8",
-          weight: 3,
-          fillColor: "#a32f1b",
-          fillOpacity: 1,
-        }).addTo(map);
+      for (const group of groupMapLocations(locations)) {
+        const firstUser = group.locations[0]!;
+        const isGrouped = group.count > 1;
+        const marker = isGrouped
+          ? leaflet.marker([group.latitude, group.longitude], {
+              icon: leaflet.divIcon({
+                className: "map-user-cluster",
+                html: `<span aria-hidden="true">${group.count}</span>`,
+                iconAnchor: [18, 18],
+                iconSize: [36, 36],
+              }),
+              keyboard: true,
+            }).addTo(map)
+          : leaflet.circleMarker([group.latitude, group.longitude], {
+              radius: 8,
+              color: "#eee8d8",
+              weight: 3,
+              fillColor: "#a32f1b",
+              fillOpacity: 1,
+            }).addTo(map);
         const tooltip = document.createElement("span");
-        tooltip.textContent = `${user.nickname} · ${user.location}`;
+        tooltip.textContent = isGrouped
+          ? `${group.count} users · ${group.nicknames.join(" · ")}`
+          : `${firstUser.nickname} · ${firstUser.location}`;
         marker.bindTooltip(tooltip, { direction: "top" });
-        const userPath = `/admin/users/${user.userId}`;
-        marker.on("click", () => window.location.assign(userPath));
+
+        if (isGrouped) {
+          const popup = document.createElement("div");
+          const heading = document.createElement("strong");
+          heading.textContent = `${group.count} users near ${firstUser.location}`;
+          popup.append(heading);
+          const list = document.createElement("ul");
+          for (const user of group.locations) {
+            const item = document.createElement("li");
+            const link = document.createElement("a");
+            link.href = `/admin/users/${user.userId}`;
+            link.textContent = user.nickname;
+            item.append(link);
+            list.append(item);
+          }
+          popup.append(list);
+          marker.bindPopup(popup);
+        } else {
+          marker.on("click", () => window.location.assign(`/admin/users/${firstUser.userId}`));
+        }
+
         const element = marker.getElement();
-        element?.setAttribute("aria-label", `${user.nickname}, ${user.location}`);
-        element?.setAttribute("role", "link");
+        const label = isGrouped
+          ? `${group.count} users near ${firstUser.location}: ${group.nicknames.join(", ")}`
+          : `${firstUser.nickname}, ${firstUser.location}`;
+        element?.setAttribute("aria-label", label);
+        element?.setAttribute("role", isGrouped ? "button" : "link");
         element?.setAttribute("tabindex", "0");
+        if (isGrouped) {
+          element?.setAttribute("aria-haspopup", "dialog");
+          element?.setAttribute("aria-expanded", "false");
+          marker.on("popupopen", () => element?.setAttribute("aria-expanded", "true"));
+          marker.on("popupclose", () => element?.setAttribute("aria-expanded", "false"));
+        }
         element?.addEventListener("focus", () => marker.openTooltip());
         element?.addEventListener("blur", () => marker.closeTooltip());
         element?.addEventListener("keydown", (event) => {
           const keyboardEvent = event as KeyboardEvent;
           if (keyboardEvent.key === "Enter" || keyboardEvent.key === " ") {
             keyboardEvent.preventDefault();
-            window.location.assign(userPath);
+            if (isGrouped) marker.openPopup();
+            else window.location.assign(`/admin/users/${firstUser.userId}`);
           }
         });
-        bounds.push([user.latitude, user.longitude]);
+        bounds.push([group.latitude, group.longitude]);
       }
       if (bounds.length) map.fitBounds(bounds, { padding: [40, 40], maxZoom: 6 });
       cleanup = () => map.remove();

apps/web/src/components/user-world-map.test.tsx

@@ -15,6 +15,17 @@ describe("UserWorldMap", () => {
       classification: "clear",
       source: "game",
       observedAt: new Date("2026-08-01T12:00:00Z"),
+    }, {
+      userId: "22222222-2222-4222-8222-222222222222",
+      name: "Alex",
+      discordUsername: "alex",
+      nickname: "Alex (AlexMC)",
+      latitude: 37.4057,
+      longitude: -122.0774,
+      location: "Mountain View, California, US",
+      classification: "clear",
+      source: "web",
+      observedAt: new Date("2026-08-01T13:00:00Z"),
     }]} unavailableCount={2} />);
 
     expect(markup).toContain('role="group"');
@@ -22,6 +33,10 @@ describe("UserWorldMap", () => {
     expect(markup).toContain("Latest approximate location for registered users");
     expect(markup).toContain('href="/admin/users/11111111-1111-4111-8111-111111111111"');
     expect(markup).toContain("Dani (Steve)");
+    expect(markup).toContain("Alex (AlexMC)");
+    expect(markup).toContain("2 users near Mountain View, California, US");
+    expect(markup).toMatch(/<text[^>]*>2<\/text>/);
+    expect(markup).toContain('<details class="mt-5 border-t border-line pt-4" id="map-location-list" open="">');
     expect(markup).toContain("Mountain View, California, US");
     expect(markup).toContain("World overview");
     expect(markup).toContain("Interactive OpenStreetMap");

apps/web/src/components/user-world-map.tsx

@@ -4,6 +4,7 @@ import { geoEquirectangular, geoPath } from "d3-geo";
 import { feature } from "topojson-client";
 import countriesTopologyJson from "world-atlas/countries-110m.json";
 import Link from "next/link";
+import { groupMapLocations } from "@/lib/user-location-map";
 import { MapViewToggle } from "./map-view-toggle";
 
 const WIDTH = 1_000;
@@ -27,6 +28,7 @@ export interface UserMapLocation {
 }
 
 export function UserWorldMap({ locations, unavailableCount }: { locations: UserMapLocation[]; unavailableCount: number }) {
+  const locationGroups = groupMapLocations(locations);
   return (
     <section className="mt-8 border border-line bg-panel p-5 shadow-[8px_8px_0_var(--color-shadow)] sm:p-7">
       <div className="flex flex-col gap-4 sm:flex-row sm:items-end sm:justify-between">
@@ -50,23 +52,39 @@ export function UserWorldMap({ locations, unavailableCount }: { locations: UserM
             })}
           </g>
           <g>
-            {locations.map((user) => {
-              const projected = projection([user.longitude, user.latitude]);
+            {locationGroups.map((group) => {
+              const projected = projection([group.longitude, group.latitude]);
               if (!projected) return null;
-              const x = Math.min(WIDTH - 14, Math.max(14, projected[0]));
-              const y = Math.min(HEIGHT - 14, Math.max(14, projected[1]));
-              const tooltipWidth = Math.min(260, Math.max(110, user.nickname.length * 8 + 24));
+              const x = Math.min(WIDTH - 16, Math.max(16, projected[0]));
+              const y = Math.min(HEIGHT - 16, Math.max(16, projected[1]));
+              const markerRadius = group.count > 1 ? 13 : 7;
+              const longestNickname = Math.max(...group.nicknames.map((nickname) => nickname.length));
+              const tooltipColumns = Math.ceil(group.nicknames.length / 10);
+              const tooltipRows = Math.ceil(group.nicknames.length / tooltipColumns);
+              const tooltipWidth = Math.min(WIDTH - 8, Math.max(110, longestNickname * 8 + 24) * tooltipColumns);
+              const tooltipColumnWidth = tooltipWidth / tooltipColumns;
+              const tooltipHeight = tooltipRows * 18 + 10;
               const tooltipX = Math.min(WIDTH - tooltipWidth - 4, Math.max(4, x - tooltipWidth / 2));
-              const tooltipY = y > 46 ? y - 38 : y + 18;
+              const preferredTooltipY = y > tooltipHeight + 18 ? y - tooltipHeight - 12 : y + 18;
+              const tooltipY = Math.min(HEIGHT - tooltipHeight - 4, Math.max(4, preferredTooltipY));
+              const firstUser = group.locations[0]!;
+              const label = group.count === 1
+                ? `${firstUser.nickname}, ${firstUser.location}`
+                : `${group.count} users near ${firstUser.location}: ${group.nicknames.join(", ")}`;
               return (
-                <a aria-label={`${user.nickname}, ${user.location}, last seen ${user.observedAt.toISOString()}`} className="map-marker-link" href={`/admin/users/${user.userId}`} key={user.userId}>
-                  <circle className="map-marker-target" cx={x} cy={y} fill="none" pointerEvents="stroke" r="7" stroke="transparent" strokeWidth="24" vectorEffect="non-scaling-stroke">
-                    <title>{user.nickname} · {user.location} · {user.classification}</title>
+                <a aria-label={label} className="map-marker-link" href={group.count === 1 ? `/admin/users/${firstUser.userId}` : "#map-location-list"} key={group.key}>
+                  <circle className="map-marker-target" cx={x} cy={y} fill="none" pointerEvents="stroke" r={markerRadius} stroke="transparent" strokeWidth="24" vectorEffect="non-scaling-stroke">
+                    <title>{label}</title>
                   </circle>
-                  <circle className="map-marker" cx={x} cy={y} fill="var(--accent)" pointerEvents="none" r="7" stroke="var(--panel)" strokeWidth="3" />
+                  <circle className="map-marker" cx={x} cy={y} fill="var(--accent)" pointerEvents="none" r={markerRadius} stroke="var(--panel)" strokeWidth="3" />
+                  {group.count > 1 && <text aria-hidden="true" dominantBaseline="middle" fill="var(--panel)" fontFamily="var(--font-mono)" fontSize="12" fontWeight="700" pointerEvents="none" textAnchor="middle" x={x} y={y}>{group.count}</text>}
                   <g aria-hidden="true" className="map-marker-tooltip" pointerEvents="none">
-                    <rect fill="var(--ink)" height="28" rx="2" width={tooltipWidth} x={tooltipX} y={tooltipY} />
-                    <text dominantBaseline="middle" fill="var(--panel)" fontFamily="var(--font-mono)" fontSize="12" textAnchor="middle" x={tooltipX + tooltipWidth / 2} y={tooltipY + 14}>{user.nickname}</text>
+                    <rect fill="var(--ink)" height={tooltipHeight} rx="2" width={tooltipWidth} x={tooltipX} y={tooltipY} />
+                    {group.nicknames.map((nickname, index) => {
+                      const column = Math.floor(index / tooltipRows);
+                      const row = index % tooltipRows;
+                      return <text dominantBaseline="middle" fill="var(--panel)" fontFamily="var(--font-mono)" fontSize="12" key={`${nickname}-${index}`} textAnchor="middle" x={tooltipX + tooltipColumnWidth * (column + 0.5)} y={tooltipY + 14 + row * 18}>{nickname}</text>;
+                    })}
                   </g>
                 </a>
               );
@@ -77,7 +95,7 @@ export function UserWorldMap({ locations, unavailableCount }: { locations: UserM
       </MapViewToggle>
       <p className="mt-2 text-right font-mono text-[9px] text-muted">Map boundaries: Natural Earth, public domain</p>
 
-      <details className="mt-5 border-t border-line pt-4">
+      <details className="mt-5 border-t border-line pt-4" id="map-location-list" open={locationGroups.some((group) => group.count > 1)}>
         <summary className="w-fit cursor-pointer font-mono text-[10px] font-bold uppercase underline underline-offset-4">View accessible location list</summary>
         <div className="mt-4 overflow-x-auto">
           <table className="w-full min-w-[680px] border-collapse text-left text-xs">

apps/web/src/lib/user-location-map.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { parseUserLocation, projectWorldPoint } from "./user-location-map";
+import { groupMapLocations, parseUserLocation, projectWorldPoint } from "./user-location-map";
 
 describe("user location map", () => {
   it("extracts a valid approximate location from cached IP intelligence", () => {
@@ -24,6 +24,28 @@ describe("user location map", () => {
     expect(parseUserLocation({ location: { city: "Unknown" } })).toBeNull();
   });
 
+  it("groups users sharing approximate coordinates without hiding their identities", () => {
+    const groups = groupMapLocations([
+      { userId: "one", nickname: "Dani (Steve)", latitude: 37.4056, longitude: -122.0775 },
+      { userId: "two", nickname: "Alex (AlexMC)", latitude: 37.4057, longitude: -122.0774 },
+      { userId: "three", nickname: "Sam (Notch)", latitude: 51.5, longitude: -0.12 },
+    ]);
+
+    expect(groups).toHaveLength(2);
+    expect(groups[0]).toMatchObject({ count: 2, nicknames: ["Alex (AlexMC)", "Dani (Steve)"] });
+    expect(groups[0]?.locations.map((location) => location.userId)).toEqual(["one", "two"]);
+    expect(groups[1]).toMatchObject({ count: 1, nicknames: ["Sam (Notch)"] });
+  });
+
+  it("normalizes signed zero and the antimeridian before grouping", () => {
+    const groups = groupMapLocations([
+      { nickname: "West", latitude: -0.004, longitude: 180 },
+      { nickname: "East", latitude: 0.004, longitude: -180 },
+    ]);
+    expect(groups).toHaveLength(1);
+    expect(groups[0]).toMatchObject({ count: 2, key: "0:-180", latitude: 0, longitude: -180 });
+  });
+
   it("projects longitude and latitude into an equirectangular SVG", () => {
     expect(projectWorldPoint(0, 0, 800, 400)).toEqual({ x: 400, y: 200 });
     expect(projectWorldPoint(90, 180, 800, 400)).toEqual({ x: 800, y: 0 });

apps/web/src/lib/user-location-map.ts

@@ -33,6 +33,32 @@ export function parseUserLocation(value: unknown): ParsedUserLocation | null {
   return { latitude, longitude, label: label || "Approximate location unavailable" };
 }
 
+export function groupMapLocations<T extends {
+  latitude: number;
+  longitude: number;
+  nickname: string;
+}>(locations: T[]) {
+  const grouped = new Map<string, { latitude: number; longitude: number; locations: T[] }>();
+  for (const location of locations) {
+    const roundedLatitude = Number(location.latitude.toFixed(2));
+    const latitude = roundedLatitude === 0 ? 0 : roundedLatitude;
+    const roundedLongitude = Number(location.longitude.toFixed(2));
+    const longitude = Math.abs(roundedLongitude) === 180 ? -180 : roundedLongitude;
+    const key = `${latitude}:${longitude}`;
+    const group = grouped.get(key);
+    if (group) group.locations.push(location);
+    else grouped.set(key, { latitude, longitude, locations: [location] });
+  }
+  return [...grouped.entries()].map(([key, group]) => ({
+    key,
+    latitude: group.latitude,
+    longitude: group.longitude,
+    count: group.locations.length,
+    nicknames: [...group.locations.map((location) => location.nickname)].sort((left, right) => left.localeCompare(right)),
+    locations: group.locations,
+  }));
+}
+
 export function projectWorldPoint(latitude: number, longitude: number, width: number, height: number) {
   return {
     x: ((longitude + 180) / 360) * width,