相模野基線, survey baseline in Kanagawa Prefecture, Japan

The Sagamino Baseline is a surveying line that runs approximately 5.2 kilometers between two triangulation points in the northeastern region of Kanagawa Prefecture. It connects three measurement stations: the northern point at Shimogoumura, the southern point at Zamamura, and a midpoint triangulation station.

This baseline was established in 1882 by the Army General Staff Survey Division as the foundation for Japan's first national triangulation network. It marked the beginning of a series of fourteen survey lines constructed between 1882 and 1911 to support the country's national mapping project.

The southern marker in Zama City and the northern marker in Sagamihara City both hold the status of Important Cultural Properties in their respective municipalities. They reflect how these survey points were valued as part of the nation's modernization efforts.

The marker points are located within the cities of Sagamihara and Zama and are accessible for visitors to see. It helps to plan ahead and learn directions to each point, as they are spread across a wide area.

This baseline holds the distinction of being the oldest of the fourteen survey lines built during that era and remains a testament to Japan's early modern surveying technology. The precise markers still visible today show the careful craftsmanship and accuracy that went into surveying work in the 1880s.