diff --git a/src/lib/geo.test.ts b/src/lib/geo.test.ts
new file mode 100644
index 0000000..7c3d2a3
--- /dev/null
+++ b/src/lib/geo.test.ts
@@ -0,0 +1,96 @@
+import { describe, expect, it } from "vitest";
+
+import { driverLabelFor, unassignedGlyphFor } from "./geo";
+
+describe("driverLabelFor", () => {
+  it("returns A for the first driver alphabetically", () => {
+    const drivers = [{ id: "u-1" }, { id: "u-2" }].sort((a, b) =>
+      a.id.localeCompare(b.id)
+    );
+    // u-1 < u-2 lexically, so driver at index 0 is "u-1"
+    expect(driverLabelFor(drivers, drivers[0].id)).toBe("A");
+    expect(driverLabelFor(drivers, drivers[1].id)).toBe("B");
+  });
+
+  it("returns sequential letters A through Z for the first 26 drivers", () => {
+    const drivers = Array.from({ length: 26 }, (_, i) => ({
+      id: `driver-${String(i).padStart(2, "0")}`,
+    }));
+    const sorted = [...drivers].sort((a, b) => a.id.localeCompare(b.id));
+    for (let i = 0; i < 26; i++) {
+      expect(driverLabelFor(sorted, sorted[i].id)).toBe(
+        String.fromCharCode("A".charCodeAt(0) + i)
+      );
+    }
+  });
+
+  it("falls back to digits 1..9 starting at position 27", () => {
+    const drivers = Array.from({ length: 30 }, (_, i) => ({
+      id: `driver-${String(i).padStart(2, "0")}`,
+    }));
+    const sorted = [...drivers].sort((a, b) => a.id.localeCompare(b.id));
+    expect(driverLabelFor(sorted, sorted[26].id)).toBe("1");
+    expect(driverLabelFor(sorted, sorted[27].id)).toBe("2");
+    expect(driverLabelFor(sorted, sorted[28].id)).toBe("3");
+    expect(driverLabelFor(sorted, sorted[29].id)).toBe("4");
+  });
+
+  it("returns '?' for an unknown driver id", () => {
+    const drivers = [{ id: "u-1" }];
+    expect(driverLabelFor(drivers, "u-missing")).toBe("?");
+  });
+
+  it("is stable — same input returns the same label on repeated calls", () => {
+    const drivers = [{ id: "u-1" }, { id: "u-2" }, { id: "u-3" }];
+    const sorted = [...drivers].sort((a, b) => a.id.localeCompare(b.id));
+    const first = driverLabelFor(sorted, "u-2");
+    const second = driverLabelFor(sorted, "u-2");
+    const third = driverLabelFor(sorted, "u-2");
+    expect(first).toBe(second);
+    expect(second).toBe(third);
+  });
+
+  it("is stable when given names instead of ids (alphabetical by name)", () => {
+    const drivers = [
+      { id: "alice" },
+      { id: "bob" },
+      { id: "carol" },
+    ];
+    expect(driverLabelFor(drivers, "alice")).toBe("A");
+    expect(driverLabelFor(drivers, "bob")).toBe("B");
+    expect(driverLabelFor(drivers, "carol")).toBe("C");
+  });
+});
+
+describe("unassignedGlyphFor", () => {
+  it("returns 'ready' when every item is ready_for_collection=true", () => {
+    expect(
+      unassignedGlyphFor([
+        { ready_for_collection: true },
+        { ready_for_collection: true },
+      ])
+    ).toBe("ready");
+  });
+
+  it("returns 'unready' when at least one item is not ready", () => {
+    expect(
+      unassignedGlyphFor([
+        { ready_for_collection: true },
+        { ready_for_collection: false },
+      ])
+    ).toBe("unready");
+  });
+
+  it("returns 'unready' when at least one item has ready_for_collection=undefined", () => {
+    expect(
+      unassignedGlyphFor([
+        { ready_for_collection: true },
+        {},
+      ])
+    ).toBe("unready");
+  });
+
+  it("returns 'unready' for an empty array", () => {
+    expect(unassignedGlyphFor([])).toBe("unready");
+  });
+});
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diff --git a/src/lib/geo.ts b/src/lib/geo.ts
index 87a2dbe..f672970 100644
--- a/src/lib/geo.ts
+++ b/src/lib/geo.ts
@@ -226,4 +226,55 @@ export function colorForStop(args: {
     default:
       return DRIVER_PALETTE[args.driverIndex] ?? DRIVER_PALETTE[0];
   }
+}
+
+/* ============================================================================
+ * Collection map — pin label + glyph helpers.
+ *
+ * Pure functions that drive the new two-pin model on the collection map.
+ * Driver labels are alphabetical by id (A → Z, then 1 → 9); the unassigned
+ * glyph collapses ready / unready into ✓ / ✕ based on the bucket contents.
+ * ========================================================================= */
+
+/**
+ * Returns the driver label for a given driver id within an alphabetically-
+ * sorted driver list. Position 0 → "A", 1 → "B", ..., 25 → "Z", 26 → "1",
+ * 27 → "2", ... Returns "?" if the id isn't in the list.
+ *
+ * The caller MUST pass a list already sorted by `id` ascending — typically
+ * the `driversWithItems` array, which `page.tsx` already sorts by name via
+ * `localeCompare` on the matching `LookupUser` record. Because driver
+ * `id` and driver `name` are stable across days, the letter for a given
+ * driver is also stable across days.
+ */
+export function driverLabelFor(
+  sortedDrivers: { id: string }[],
+  driverId: string
+): string {
+  const idx = sortedDrivers.findIndex((d) => d.id === driverId);
+  if (idx === -1) return "?";
+  if (idx < 26) return String.fromCharCode("A".charCodeAt(0) + idx);
+  // After Z, fall back to 1..9 (and then loop — at >35 drivers we'll
+  // reuse digits, which is a graceful degradation rather than a crash).
+  return String((idx - 25) % 10);
+}
+
+/**
+ * Returns the unassigned glyph for a supplier bucket:
+ *   - "ready"   → ✓ : every pool item has ready_for_collection === true.
+ *   - "unready" → ✕ : at least one isn't ready, or the bucket is empty.
+ *
+ * Returning "unready" for an empty input keeps the pin from falsely
+ * advertising "ready, 0 items" — an empty bucket shouldn't render a pin
+ * at all, but if the caller asks the helper for the glyph defensively,
+ * "unready" is the safer answer.
+ */
+export function unassignedGlyphFor(
+  poolItems: { ready_for_collection?: boolean }[]
+): "ready" | "unready" {
+  if (poolItems.length === 0) return "unready";
+  const anyUnready = poolItems.some(
+    (it) => it.ready_for_collection !== true
+  );
+  return anyUnready ? "unready" : "ready";
 }
\ No newline at end of file