The meridian system is one of the world's oldest medical models, with roots stretching back over two millennia. The foundational text, the , describes a system of meridians and points that has guided acupuncture practice for more than 2,000 years .
Everything east of the Prime Meridian up to 180° (including Europe, Africa, Asia, and Australia). meridian coordinates
Meridian coordinates are a fundamental part of any , which is a three-dimensional reference framework used to define locations on the Earth's surface. A GCS uses a three-dimensional spherical surface, with locations referenced by angular measurements, and includes an angular unit, a prime meridian, and a datum. The coordinates are spherical coordinates that express a point's location using latitude and longitude. The meridian system is one of the world's