Quick Reference
UTM Format: Zone + Letter + Easting + Northing (e.g., 51S 377561 4621522)
Example: 40.7128N, -74.0060W = 18T 583959 4507351
Pro Tip: Each UTM zone is 6 wide. Crossing zone boundaries without recomputing causes severe false easting discontinuities (~500+ km) across zone boundaries in autonomous navigation engines.
UTMゾーン参照テーブル（主要都市）
Quick reference for which UTM zone covers major world cities:
| City | Lat/Long | UTM Zone | UTM Coordinates |
|---|---|---|---|
| New York, USA | 40.7128N, 74.0060W | 18T | 583959 E, 4507351 N |
| London, UK | 51.5074N, 0.1278W | 30U | 699316 E, 5710164 N |
| Tokyo, Japan | 35.6762N, 139.6503E | 54S | 377856 E, 3948874 N |
| Sydney, Australia | 33.8688S, 151.2093E | 56H | 334369 E, 6250948 N |
| Paris, France | 48.8566N, 2.3522E | 31U | 452483 E, 5411717 N |
| São Paulo, Brazil | 23.5505S, 46.6333W | 23K | 333398 E, 7394541 N |
よくあるご質問 (FAQ)
What is UTM and why use it instead of lat/long?
UTM (ユニバーサル横メルカトル図法) divides Earth into 60 zones, each 6 wide, with a uniform scale factor. Unlike lat/long, UTM coordinates are in meters, making distance calculations and GIS analysis simpler. UTM is the standard for engineering, construction, and many government agencies (USGS, FEMA, military).
What is the UTM zone letter and why does it matter?
The letter indicates latitude bands (C–X, excluding I and O). The zone number indicates longitude (1–60, starting from 180W). Both zone and letter are critical, using the wrong combination places your coordinates thousands of kilometers away.
What causes the 554km "robot snap" error?
When a vehicle or robot crosses a UTM zone boundary, its x/y coordinates jump dramatically (because each zone has its own easting origin). If the system doesn't recompute the UTM zone, the robot perceives itself 554km away. This caused an autonomous lawnmower to fail mid-operation.
What is the UTM scale factor (0.9996) and how does elevation affect it?
UTM uses a scale factor of 0.9996 at the central meridian of each zone to minimize distortion. At zone edges, distortion reaches ±0.04%. At high elevation (e.g., 1000m above sea level), the effective scale factor drifts, causing 15cm/km errors in mountainous terrain. SAR (検索 and Rescue) operations must account for this.
縮尺係数の歪みとSPCSの工学的責任
標高差の大きい山岳SPCSゾーン（コロラド州やカリフォルニア州など）では、合成縮尺係数の誤差が1kmあたり15cmに達することがあります。グリッド座標（投影平面）を地上距離として補正なしで扱うと、重大な施工ミスや杭位置の誤認につながります。