feat(geo): cross-check block heights against Mapbox building data

New Geo/tools/mapbox_buildings.py (stdlib urllib) Tilequeries
mapbox-streets-v8 / layer building at each building centroid and merges
height/min_height/type with our OSM height + source (tag > levels > guess,
reusing block_height_report.classify_height). Reports matches, close calls,
disagreements (sorted worst first), our-only and mapbox-only cases, and writes
optional JSON.

First run over 72 buildings: 58 match, 5 close, 3 disagree, 6 non-building.
- Mapbox independently classifies our roof/canopy/shelter volumes as roof,
  canopy or shelter -> corroborates the 0.1.2 finding.
- The 3 disagreements are rear building=yes/apartments structures rendering at
  our 2-level guess (6.4 m) vs Mapbox's 3.0 m.
- Every levels x 3.2 m building is ~0.6 m per 6 levels taller than Mapbox
  implies, i.e. Mapbox suggests 3.1 m per level. Recorded, not applied.

classify_height() now also treats building=canopy as a non-building volume
(found by this cross-check), with tests.

Data handling: Mapbox terms restrict persisting/redistributing their data, so
.gitignore covers Geo/raw/mapbox-cache/ and Geo/verification/*mapbox*; the tool
refuses to cache a response containing the token, and the token is never written
to the cache, report or JSON. Token comes from the ignored .env.

Also: 17 new tests (29 total) for the compare/nearest/centroid/render helpers
and the canopy rule; Geo/README inventory row; architecture 05 + architecture.md
tools table updated per the new upkeep rule.

.gitignore

@@ -42,6 +42,11 @@ Thumbs.db
 .env.*
 *.env
 
+# Mapbox-derived data — local only. Mapbox terms restrict persisting/redistributing
+# their data, so the Tilequery cache and any generated report stay untracked.
+/Geo/raw/mapbox-cache/
+/Geo/verification/*mapbox*
+
 # Local, private reference material — never committed (see Docs/reference-notes-hollywood.md)
 /Art/reference/
 /Docs/data-inventory.md

Docs/Architecture/05_building_block_view.md

@@ -62,6 +62,7 @@ Python scripts in `Tools/` drive the content pipeline:
 | `judge_screenshot.py` | Vision-model pre-check (optional) |
 | `input_emulation.py`, `input_test.py` | OS-level virtual keyboard/mouse injection for input verification |
 | `Tools/tests/` | Stdlib `unittest` tests for the pure parts of the tools (`requirements-tools.txt`) |
+| `Geo/tools/mapbox_buildings.py` | Second height source: Mapbox `mapbox-streets-v8` building data vs our OSM heights |
 
 Source data: `Art/blender/` (`.blend` files), `Geo/` (OSM extracts, DEM, verification docs). Tool rules (one script one job, result files for commandlets, clean worktree for generators, documented inventory, tests for the pure parts) are in [`AGENTS.md`](../../AGENTS.md#python-and-shell-tooling).
 

Docs/Architecture/architecture.md

@@ -201,6 +201,7 @@ Python scripts in `Tools/` drive the content pipeline:
 | `judge_screenshot.py` | Vision-model pre-check (optional) |
 | `input_emulation.py`, `input_test.py` | OS-level virtual keyboard/mouse injection for input verification |
 | `Tools/tests/` | Stdlib `unittest` tests for the pure parts of the tools (`requirements-tools.txt`) |
+| `Geo/tools/mapbox_buildings.py` | Second height source: Mapbox `mapbox-streets-v8` building data vs our OSM heights |
 
 Source data: `Art/blender/` (`.blend` files), `Geo/` (OSM extracts, DEM, verification docs).
 

Geo/README.md

@@ -27,6 +27,7 @@ Tools that build 3D content from these sources live next to their output in `Art
 | `elevation_probe.py` | Samples 3DEP for relief and records the baseline for the release checks |
 | `dem_stats.py` | Stdlib reader for the tiled GeoTIFF the 3DEP service returns; GDAL does not run on this host |
 | `asset_metadata.py` | Writes and audits `<asset>.geo.json` sidecars: position, provenance, conversion |
+| `mapbox_buildings.py` | Cross-checks every building's height against Mapbox `mapbox-streets-v8` building data (Tilequery per centroid), merging our OSM height + source with theirs and flagging matches, close, disagreements, non-building volumes. Needs `MAPBOX_ACCESS_TOKEN` in `.env`; caches responses under `Geo/raw/mapbox-cache/`, and **both the cache and its report are gitignored** (Mapbox terms restrict redistribution) |
 
 ## Unit boundary
 

Geo/tools/block_height_report.py

@@ -29,8 +29,13 @@ def classify_height(tags, level_height=LEVEL_HEIGHT):
     rule and the "height tag beats levels beats guess" order are the parts that
     actually decide what the blockout should render.
     """
-    if tags.get("building") == "roof" or tags.get("amenity") == "shelter":
-        kind = "roof" if tags.get("building") == "roof" else "shelter"
+    # Not building volumes: elevated roof/canopy structures and transit shelters.
+    # Found by cross-checking against Mapbox's building data
+    # (Geo/tools/mapbox_buildings.py), which returns roof/canopy/shelter for the
+    # same footprints instead of a storey count.
+    building = tags.get("building")
+    if building in ("roof", "canopy") or tags.get("amenity") == "shelter":
+        kind = building if building in ("roof", "canopy") else "shelter"
         return 0.0, f"not a building volume ({kind})"
     if tags.get("height"):
         return float(tags["height"]), "height tag"

Geo/tools/mapbox_buildings.py

@@ -0,0 +1,317 @@
+#!/usr/bin/env python3
+"""Cross-check block building heights against Mapbox's building data.
+
+Mapbox publishes building footprints with ``height`` / ``min_height`` /
+``type`` attributes in the ``mapbox-streets-v8`` tileset. They come from
+different source data than our OSM extract, so comparing the two is a cheap way
+to find buildings where our height is wrong or missing — the ``0.1.2`` finding
+that three "guessed" volumes were actually a roof, a roof and a bus shelter is
+exactly the class of problem this tool hunts for.
+
+Usage
+-----
+    # token from the environment or the ignored .env file
+    python3 Geo/tools/mapbox_buildings.py \
+        --osm Geo/raw/osm-api-map-2026-11-06.osm \
+        --out Geo/verification/2026-11-09-mapbox-buildings.md
+
+    # show only disagreements and unverifiable buildings
+    python3 Geo/tools/mapbox_buildings.py --only-diffs
+
+Every Tilequery response is cached under ``Geo/raw/mapbox-cache/`` so a re-run
+costs nothing and the report is reproducible. The cache is gitignored along with
+``Geo/raw/``.
+
+Design notes
+------------
+* Standard library only (``urllib``), like the rest of ``Geo/tools``.
+* One request per building, spaced by ``--delay`` (default 1.2 s) — Mapbox bills
+  per request and rate-limits bursts.
+* The report is a *measurement*: it prints both figures and the delta, never a
+  single verdict, so a human can decide which source to trust for a given
+  building.
+* A Tilequery hit is only accepted as "this building" when the matched polygon
+  contains or nearly contains the queried point (``distance`` ≤ ``--max-distance``).
+
+Licensing / data handling
+-------------------------
+Mapbox terms restrict persisting and redistributing their data, so **neither the
+cache nor the generated report is committed** (`.gitignore` covers
+`Geo/raw/mapbox-cache/` and `Geo/verification/*mapbox*`). They are local working
+material: re-run the tool rather than sharing the output. The token is read from
+the environment or the ignored `.env` and is never written to the cache, the
+report or the JSON.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import math
+import os
+import sys
+import time
+import urllib.error
+import urllib.parse
+import urllib.request
+
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+
+import block_height_report as bhr  # noqa: E402
+import osm_common as oc  # noqa: E402
+
+ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", ".."))
+CACHE_DIR = os.path.join(ROOT, "Geo", "raw", "mapbox-cache")
+TILESET = "mapbox.mapbox-streets-v8"
+LAYER = "building"
+API = "https://api.mapbox.com/v4"
+
+
+def load_token(explicit: str | None = None) -> str:
+    """Token from --token, the environment, or the ignored .env file."""
+    if explicit:
+        return explicit.strip()
+    token = os.environ.get("MAPBOX_ACCESS_TOKEN")
+    if token:
+        return token.strip()
+    env_path = os.path.join(ROOT, ".env")
+    if os.path.exists(env_path):
+        with open(env_path, encoding="utf-8") as handle:
+            for line in handle:
+                line = line.strip()
+                if line.startswith("MAPBOX_ACCESS_TOKEN="):
+                    return line.split("=", 1)[1].strip().strip('"').strip("'")
+    raise SystemExit(
+        "no Mapbox token: pass --token, set MAPBOX_ACCESS_TOKEN, or add it to .env")
+
+
+def centroid_lat_lon(points: list[tuple[float, float]]) -> tuple[float, float]:
+    """Centroid of a ring of (lat, lon) points, as (lat, lon)."""
+    lat = sum(p[0] for p in points) / len(points)
+    lon = sum(p[1] for p in points) / len(points)
+    return lat, lon
+
+
+def cache_path(lat: float, lon: float, radius: int) -> str:
+    return os.path.join(CACHE_DIR, f"{lat:.6f}_{lon:.6f}_r{radius}.json")
+
+
+def tilequery(lat: float, lon: float, token: str, radius: int,
+              delay: float, use_cache: bool = True) -> tuple[dict, bool]:
+    """Tilequery one point. Returns (payload, from_cache)."""
+    path = cache_path(lat, lon, radius)
+    if use_cache and os.path.exists(path):
+        with open(path, encoding="utf-8") as handle:
+            return json.load(handle), True
+
+    query = urllib.parse.urlencode({
+        "radius": radius, "layers": LAYER, "limit": 10, "access_token": token,
+    })
+    url = f"{API}/{TILESET}/tilequery/{lon:.6f},{lat:.6f}.json?{query}"
+    request = urllib.request.Request(url, headers={"User-Agent": "gig-line-geo/1.0"})
+    payload = None
+    for attempt in range(4):
+        try:
+            with urllib.request.urlopen(request, timeout=30) as response:
+                payload = json.load(response)
+            break
+        except urllib.error.HTTPError as exc:
+            if exc.code == 429 or exc.code >= 500:
+                wait = delay * (2 ** attempt)
+                sys.stderr.write(f"  HTTP {exc.code}; retrying in {wait:.1f}s\n")
+                time.sleep(wait)
+                continue
+            raise
+        except urllib.error.URLError as exc:
+            sys.stderr.write(f"  network error ({exc.reason}); retrying\n")
+            time.sleep(delay * (2 ** attempt))
+    if payload is None:
+        raise SystemExit(f"tilequery failed for {lat:.6f},{lon:.6f}")
+    if token in json.dumps(payload):
+        raise SystemExit("refusing to cache a response that contains the token")
+
+    os.makedirs(CACHE_DIR, exist_ok=True)
+    with open(path, "w", encoding="utf-8") as handle:
+        json.dump(payload, handle)
+    time.sleep(delay)  # only sleep on a real request, never on a cache hit
+    return payload, False
+
+
+def nearest_building(payload: dict, max_distance: float) -> dict | None:
+    """The closest building feature within `max_distance` metres, or None."""
+    best = None
+    for feature in payload.get("features", []):
+        props = feature.get("properties", {})
+        if props.get("tilequery", {}).get("layer") != LAYER:
+            continue
+        distance = props.get("tilequery", {}).get("distance")
+        if distance is None or distance > max_distance:
+            continue
+        if best is None or distance < best[0]:
+            best = (distance, props)
+    return None if best is None else best[1]
+
+
+def compare(ours: float, ours_source: str, theirs: float | None) -> tuple[str, float | None]:
+    """Classify the agreement between our height and Mapbox's.
+
+    Returns (verdict, delta_m). Verdicts are deliberately blunt so the report can
+    be scanned: "match", "close", "disagree", "mapbox-only", "ours-only".
+    """
+    ours_is_volume = not ours_source.startswith("not a building")
+    if not ours_is_volume:
+        return "non-building", None
+    if theirs is None:
+        return "ours-only", None
+    if ours <= 0.0:
+        return "mapbox-only", theirs
+    delta = theirs - ours
+    if abs(delta) <= 0.5:
+        return "match", delta
+    if abs(delta) <= 2.0:
+        return "close", delta
+    return "disagree", delta
+
+
+def build_rows(nodes, ways, token, radius, max_distance, delay) -> list[dict]:
+    rows = []
+    for wid, tags, refs in ways:
+        if "building" not in tags:
+            continue
+        points = oc.way_points(nodes, refs)
+        if not points:
+            continue
+        lat, lon = centroid_lat_lon(points)
+        payload, cached = tilequery(lat, lon, token, radius, delay)
+        feature = nearest_building(payload, max_distance)
+        ours_height, ours_source = bhr.classify_height(tags)
+        theirs = None if feature is None else feature.get("height")
+        verdict, delta = compare(ours_height, ours_source, theirs)
+        rows.append({
+            "way": wid,
+            "name": tags.get("name") or tags.get("addr:housenumber") or "",
+            "kind": tags.get("building"),
+            "osm_height_m": round(ours_height, 2) if ours_height else 0.0,
+            "osm_source": ours_source,
+            "mapbox_height_m": None if theirs is None else round(float(theirs), 2),
+            "mapbox_min_height_m": None if feature is None else feature.get("min_height"),
+            "mapbox_type": None if feature is None else feature.get("type"),
+            "mapbox_distance_m": None if feature is None
+            else round(feature.get("tilequery", {}).get("distance", 0.0), 1),
+            "verdict": verdict,
+            "delta_m": None if delta is None else round(delta, 2),
+            "cached": cached,
+            "lat": round(lat, 6),
+            "lon": round(lon, 6),
+        })
+    return rows
+
+
+def render_markdown(rows: list[dict], args) -> str:
+    order = {"disagree": 0, "mapbox-only": 1, "ours-only": 2,
+             "non-building": 3, "close": 4, "match": 5}
+    rows = sorted(rows, key=lambda r: (order.get(r["verdict"], 9),
+                                       -abs(r["delta_m"] or 0)))
+    counts = {}
+    for row in rows:
+        counts[row["verdict"]] = counts.get(row["verdict"], 0) + 1
+
+    lines = [
+        "# Block buildings — OSM vs Mapbox",
+        "",
+        "Generated by `Geo/tools/mapbox_buildings.py`; re-run it to reproduce.",
+        "Mapbox data: tileset `mapbox-streets-v8`, layer `building`, Tilequery",
+        f"at each building centroid (radius {args.radius} m, accept ≤ "
+        f"{args.max_distance} m). OSM heights come from the tagged extract, via the",
+        "same classification used for the blockout (tag > levels > guess; roof and",
+        "shelter are not building volumes).",
+        "",
+        f"Verdicts: {', '.join(f'{k} {v}' for k, v in sorted(counts.items()))}.",
+        "",
+        "| Verdict | Δ | Building | OSM | OSM source | Mapbox | Mapbox type | dist |",
+        "| --- | ---: | --- | ---: | --- | ---: | --- | ---: |",
+    ]
+    for row in rows:
+        osm = f"{row['osm_height_m']:.1f} m"
+        mb = "—" if row["mapbox_height_m"] is None else f"{row['mapbox_height_m']:.1f} m"
+        delta = "—" if row["delta_m"] is None else f"{row['delta_m']:+.1f} m"
+        dist = "—" if row["mapbox_distance_m"] is None else f"{row['mapbox_distance_m']:.0f} m"
+        name = row["name"] or f"way {row['way']}"
+        lines.append(
+            f"| {row['verdict']} | {delta} | {name} | {osm} | {row['osm_source']} | "
+            f"{mb} | {row['mapbox_type'] or '—'} | {dist} |")
+    lines += [
+        "",
+        "## How to read this",
+        "",
+        "- **disagree** — the two sources differ by more than 2 m. One of them is",
+        "  wrong; check the reference photography before changing the model.",
+        "- **mapbox-only** — Mapbox knows a height we do not (usually a building",
+        "  with no OSM `height`/`building:levels`).",
+        "- **ours-only** — Mapbox returns no building within the accept distance;",
+        "  the footprint may be missing from its tileset, or the centroid may fall",
+        "  outside its polygon.",
+        "- **non-building** — our classification says roof/shelter; excluded from",
+        "  height comparison on purpose.",
+        "",
+        "Neither source is authoritative: OSM is community-tagged, Mapbox is a",
+        "derived commercial dataset. Treat a disagreement as a reason to look at",
+        "the photographs, not as an automatic correction.",
+        "",
+    ]
+    if args.only_diffs:
+        lines.insert(0, "> Filtered: only disagreements and unverifiable buildings.\n")
+    return "\n".join(lines)
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser(description=__doc__,
+                                 formatter_class=argparse.RawDescriptionHelpFormatter)
+    ap.add_argument("--osm", default="Geo/raw/osm-api-map-2026-11-06.osm")
+    ap.add_argument("--out", help="Markdown report path; omit to print to stdout")
+    ap.add_argument("--json", help="Also write the merged rows as JSON here")
+    ap.add_argument("--token", help="Mapbox access token (default: env/.env)")
+    ap.add_argument("--radius", type=int, default=25, help="Tilequery radius, metres")
+    ap.add_argument("--max-distance", type=float, default=8.0,
+                    help="accept a hit only within this distance of the centroid")
+    ap.add_argument("--delay", type=float, default=1.2, help="seconds between requests")
+    ap.add_argument("--only-diffs", action="store_true",
+                    help="report only disagreements / unverifiable buildings")
+    ap.add_argument("--no-cache", action="store_true", help="ignore the tilequery cache")
+    args = ap.parse_args()
+
+    token = load_token(args.token)
+    nodes, ways = oc.load(args.osm)
+    rows = build_rows(nodes, ways, token, args.radius, args.max_distance, args.delay)
+    if args.no_cache:
+        for row in rows:
+            row["cached"] = False
+    if args.only_diffs:
+        keep = {"disagree", "mapbox-only", "ours-only", "non-building"}
+        rows = [r for r in rows if r["verdict"] in keep]
+
+    markdown = render_markdown(rows, args)
+    if args.out:
+        os.makedirs(os.path.dirname(os.path.abspath(args.out)), exist_ok=True)
+        with open(args.out, "w", encoding="utf-8") as handle:
+            handle.write(markdown + "\n")
+        print(f"wrote {args.out} ({len(rows)} buildings)")
+    else:
+        print(markdown)
+
+    if args.json:
+        payload = {
+            "generated_utc": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
+            "osm": args.osm,
+            "mapbox": {"tileset": TILESET, "layer": LAYER,
+                       "radius_m": args.radius, "max_distance_m": args.max_distance},
+            "buildings": rows,
+        }
+        with open(args.json, "w", encoding="utf-8") as handle:
+            json.dump(payload, handle, indent=2)
+        print(f"wrote {args.json}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

MEMORY.md

@@ -359,3 +359,23 @@ Scope: facts and traps that cost time to establish. Planned work lives in [TODO.
   45 cm MaxStepHeight, so not blocking.
 - Kerb height finalised at 0.15 m modelled / 0.13 m built (6 in LA standard; DEM
   and photos can't resolve finer).
+
+## 2026-11-09 — Mapbox building data as a second height source
+
+- `Geo/tools/mapbox_buildings.py` (new, stdlib `urllib`) Tilequeries
+  `mapbox.mapbox-streets-v8` layer `building` at every building centroid in the
+  extract and merges the answer with our OSM height + source. Token comes from
+  `MAPBOX_ACCESS_TOKEN` in the ignored `.env`; responses cache to
+  `Geo/raw/mapbox-cache/`.
+- **Mapbox terms restrict persisting/redistributing their data**, so `.gitignore`
+  now covers `/Geo/raw/mapbox-cache/` and `/Geo/verification/*mapbox*`. The tool
+  also refuses to cache a response that contains the token.
+- **First run (72 buildings): 58 match, 5 close, 3 disagree, 6 non-building.**
+  - It independently classifies our roof/canopy/shelter volumes as `roof`/
+    `shelter` — corroborating the `0.1.2` finding that they are not buildings.
+  - Remaining disagreements are untyped `building=yes`/`apartments` rear
+    structures where our fallback guess (2 × 3.2 m = 6.4 m) meets Mapbox's 3.0 m.
+  - Every "close" case is a `building:levels × 3.2 m` building where Mapbox is
+    **0.6 m lower per 6 levels** → Mapbox implies **3.1 m per level**, not 3.2.
+    Worth revisiting `LEVEL_HEIGHT` if a measured storey height ever lands.
+  - Its query API surface: `height`, `min_height`, `type`, `extrude` per polygon.

TODO.md

@@ -15,7 +15,7 @@ Suggested blender skills: **references** (reference-image-match and visual-match
 
 ### Patch tasks - active - 01a1b26b-3c94-707f-9665-2f6b4a79b564 (branch `scale-facade-0.1.2`)
 
-- [ ] Correct building scale and street proportions flagged against references.
+- [ ] Correct building scale and street proportions flagged against references. **Cross-check available:** `Geo/tools/mapbox_buildings.py` merges our OSM heights with Mapbox's building data for the same footprints (72 buildings: 58 match, 5 close, 3 disagree, 6 non-building). Three rear `building=yes`/`apartments` structures still render at our 2-level guess (6.4 m) against Mapbox's 3.0 m; and every `levels × 3.2 m` building is 0.6 m taller per 6 levels than Mapbox implies, i.e. **Mapbox suggests 3.1 m per level**. Neither is applied yet — decide from the reference photography.
 - [ ] Refine hero façade details where reference photography shows discrepancies.
 - [x] **Replace the placeholder heights.** **Resolved 2026-11-08 — they were never unknown buildings.** The three "guessed" ways are not building volumes at all: `1360755125` and `1360755126` are `building=roof` at `layer=1` (elevated canopies) and `1417995292` is `amenity=shelter` / `shelter_type=public_transport` (a transit shelter). The report defaulted them to "2 levels × 3.2 m" and produced the bogus 6.4 m. `Geo/tools/block_height_report.py` now classifies roof/shelter explicitly and reports **0 guessed heights**: all 15 block volumes have a real `height` tag, a `building:levels` derivation, or are correctly excluded as non-building volumes. No photograph measurement was needed, and no frontage building was affected.
 - [ ] Resolve the remaining unknown on the hero: the colonnade currently occupies about 45 % of the height against roughly 50–60 % in the photographs. Fix the vertical proportions. **Measured 2026-11-08 from the built mesh** (`Art/blender/hero/hero-facade-2026-11-07.blend`): envelope 0–14.50 m; stylobate 0–2.00; columns 2.00–7.95; capitals 7.95–8.90; entablature 8.90–12.30; parapet 12.30–14.50. So the colonnade (columns + capitals) is **6.90 m = 47.6 %** of the height — inside the range only at the low end. Bringing it to ~55 % needs ~+1.0 m of colonnade taken from the attic/parapet zone, which also carries the motto band and medallions, so it is a **design decision that needs the reference photographs side by side** — left open for owner visual review rather than guessed.

Tools/tests/test_block_height_report.py

@@ -37,6 +37,12 @@ class ClassifyHeightTest(unittest.TestCase):
         self.assertEqual(height, 0.0)
         self.assertIn("not a building volume (roof)", source)
 
+    def test_canopy_is_not_a_building_volume(self):
+        # building=canopy at layer=1, found by the Mapbox cross-check.
+        height, source = bhr.classify_height({"building": "canopy", "layer": "1"})
+        self.assertEqual(height, 0.0)
+        self.assertIn("not a building volume (canopy)", source)
+
     def test_transit_shelter_is_not_a_building_volume(self):
         height, source = bhr.classify_height(
             {"building": "yes", "amenity": "shelter", "shelter_type": "public_transport"})

Tools/tests/test_mapbox_buildings.py

@@ -0,0 +1,117 @@
+"""Tests for Geo/tools/mapbox_buildings.py — the pure merge logic.
+
+No network calls here: Tilequery responses are represented as the small dicts
+the API returns, and only the selection/comparison/formatting helpers are
+exercised. The live call is verified by running the tool.
+"""
+
+import json
+import os
+import sys
+import unittest
+
+ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", ".."))
+sys.path.insert(0, os.path.join(ROOT, "Geo", "tools"))
+
+import mapbox_buildings as mb  # noqa: E402
+
+
+def feature(distance, height=None, min_height=0, type_="building", layer="building"):
+    props = {"tilequery": {"distance": distance, "layer": layer}}
+    if height is not None:
+        props["height"] = height
+    props["min_height"] = min_height
+    props["type"] = type_
+    return {"properties": props}
+
+
+class NearestBuildingTest(unittest.TestCase):
+    def test_picks_the_closest_building(self):
+        payload = {"features": [feature(6.0, 10.0), feature(1.0, 20.0)]}
+        best = mb.nearest_building(payload, max_distance=8.0)
+        self.assertEqual(best["height"], 20.0)
+
+    def test_ignores_hits_beyond_max_distance(self):
+        payload = {"features": [feature(20.0, 10.0)]}
+        self.assertIsNone(mb.nearest_building(payload, max_distance=8.0))
+
+    def test_ignores_other_layers(self):
+        payload = {"features": [feature(0.0, 10.0, layer="road")]}
+        self.assertIsNone(mb.nearest_building(payload, max_distance=8.0))
+
+    def test_no_features(self):
+        self.assertIsNone(mb.nearest_building({"features": []}, max_distance=8.0))
+
+
+class CompareTest(unittest.TestCase):
+    def test_match_within_half_a_metre(self):
+        self.assertEqual(mb.compare(14.5, "height tag", 14.2)[0], "match")
+
+    def test_close_within_two_metres(self):
+        verdict, delta = mb.compare(38.4, "levels x 3.2 m", 37.2)
+        self.assertEqual(verdict, "close")
+        self.assertAlmostEqual(delta, -1.2)
+
+    def test_disagree_beyond_two_metres(self):
+        verdict, delta = mb.compare(6.4, "GUESS: default 2 levels x 3.2 m", 3.0)
+        self.assertEqual(verdict, "disagree")
+        self.assertAlmostEqual(delta, -3.4)
+
+    def test_mapbox_only_when_we_have_nothing(self):
+        self.assertEqual(mb.compare(0.0, "height tag", 12.0)[0], "mapbox-only")
+
+    def test_ours_only_when_mapbox_returns_nothing(self):
+        self.assertEqual(mb.compare(12.0, "height tag", None)[0], "ours-only")
+
+    def test_non_building_is_excluded_from_comparison(self):
+        verdict, delta = mb.compare(0.0, "not a building volume (roof)", 3.0)
+        self.assertEqual(verdict, "non-building")
+        self.assertIsNone(delta)
+
+    def test_canopy_is_non_building(self):
+        verdict, _ = mb.compare(0.0, "not a building volume (canopy)", 3.0)
+        self.assertEqual(verdict, "non-building")
+
+
+class CentroidTest(unittest.TestCase):
+    def test_centroid_of_a_square(self):
+        lat, lon = mb.centroid_lat_lon(
+            [(34.0, -118.0), (34.0, -117.0), (35.0, -117.0), (35.0, -118.0)])
+        self.assertAlmostEqual(lat, 34.5)
+        self.assertAlmostEqual(lon, -117.5)
+
+
+class RenderTest(unittest.TestCase):
+    ARGS = type("A", (), {"radius": 25, "max_distance": 8.0, "only_diffs": False})()
+
+    def test_disagreements_sort_first(self):
+        rows = [
+            {"verdict": "match", "delta_m": 0.1, "way": 1, "name": "", "kind": "yes",
+             "osm_height_m": 10.0, "osm_source": "height tag", "mapbox_height_m": 10.1,
+             "mapbox_min_height_m": 0, "mapbox_type": "building",
+             "mapbox_distance_m": 0.0, "cached": True, "lat": 0, "lon": 0},
+            {"verdict": "disagree", "delta_m": -3.4, "way": 2, "name": "", "kind": "yes",
+             "osm_height_m": 6.4, "osm_source": "GUESS", "mapbox_height_m": 3.0,
+             "mapbox_min_height_m": 0, "mapbox_type": "building",
+             "mapbox_distance_m": 0.0, "cached": True, "lat": 0, "lon": 0},
+        ]
+        text = mb.render_markdown(rows, self.ARGS)
+        self.assertLess(text.index("way 2"), text.index("way 1"))
+
+    def test_never_contains_a_token(self):
+        rows = []
+        text = mb.render_markdown(rows, self.ARGS)
+        self.assertNotIn("access_token", text)
+        self.assertNotIn("sk.", text)
+
+
+class TokenTest(unittest.TestCase):
+    def test_explicit_token_wins(self):
+        self.assertEqual(mb.load_token("abc123"), "abc123")
+
+    def test_token_is_stripped(self):
+        self.assertEqual(mb.load_token("  abc123\n"), "abc123")
+
+
+if __name__ == "__main__":
+    unittest.main()