The first datum established in the Philippines in 1901 is named what?

• A. Manila Datum
• B. Luzon Datum
• C. Batangas Datum
• D. Vigan Datum

Answer: (D)

A datum is the fixed reference frame used for measuring positions on the Earth, including a defined origin and a model of the Earth (ellipsoid). The first datum established in the Philippines in 1901 was the Vigan Datum, named after Vigan in Ilocos Sur, which provided the initial fixed reference for horizontal surveys in the area. This set the groundwork for later datums that covered larger areas or improved accuracy, while the Manila, Luzon, and Batangas datums came after. So the Vigan Datum is the earliest named reference that began the Philippine surveying framework in 1901.