Understanding MGRS Precision Levels and Distance の座標変換 — 無料オンラインツール【2026年版】

Understanding MGRS Precision Levels and Distance

Technical Summary: The length of an MGRS coordinate directly defines the linear size of the grid square it represents, scaling from 10 kilometers down to 1 meter precision.

Professional Risk Notice

Using the wrong datum or applying coordinates without grid-to-ground correction can cause 1–400 metre positional errors — a leading cause of surveying negligence claims and contract disputes.

See Legal Cases ($25K–$10M) → Contract Datum Risk → Calculate My Exposure →

MGRS (軍用グリッド参照システム) works by defining progressively smaller grid squares. The numeric digits at the end of the coordinate dictate the exact square size.

Precision Breakdown

10-digit (e.g., 18T WL 84801 12201): 1-meter precision
8-digit (e.g., 18T WL 8480 1220): 10-meter precision
6-digit (e.g., 18T WL 848 122): 100-meter precision
4-digit (e.g., 18T WL 84 12): 1,000-meter (1 km) precision
2-digit (e.g., 18T WL 8 1): 10,000-meter (10 km) precision

Always remember that 'precision' refers to the grid cell size, not necessarily the absolute accuracy of the GPS fix taking the reading.

Verify Coordinates with Core ツール一覧

Always validate your site data before mobilizing construction or legal teams. Use our built-in coordinate converters to rule out fundamental geodetic errors:

Frequently Asked Technical Questions

What is a 10-digit MGRS coordinate accuracy?

A 10-digit MGRS coordinate represents a 1-meter by 1-meter square on the earth's surface. However, the true accuracy depends entirely on the GPS receiver establishing the coordinate.

重要：計算結果の正確性を確認してください

座標精度はデバイスや測地系によって異なります。以下の確認を行わずに実務で使用しないでください：

GPS精度の警告

スマホのGPSは最大30メートルずれることがあります。これが原因でデータに重大なエラーが発生します。

精度を今すぐチェック →

測地系のリスク

誤った測地系（例：WGS84と日本測地系）を使用すると、常に数百メートルのズレが生じます。

測地系を確認する →