Royal Thai Survey (กรมแผนที่ทหาร; September 3, 1885 - present) is a subset of the Royal Thai Armed Forces devoted to land and aerial surveys, geodesy, and geophysics. It was founded as the 'Royal Survey Department' in 1885 by Prince Damrong Rajanubhab (Tisavarakumarn; 1862 - 1943), under whose influence in 1882 King Rama V established a Royal Thai Survey School. It was renamed the Royal Thai Survey Department in 1939, when Siam was renamed Thailand. The survey department began an ambitious cadastral survey of Thailand to define land overseership and registration - mostly fort taxation purposes. The survey remains active.