 Under the Boundaries and Survey Maps (Conduct of Cadastral Surveys) Rules, the Lower Peirce Reservoir is also home of the reference point used for Singapore's geodetic co-ordinate datum or SVY21.The location is at latitude 1°22’02.915414" N, longitude 103° 49’31.975227" E and is marked by a green pillar.Under Singapore Land Authority's Guidelines and Specifications for GPS Surveys of ISN Markers, surveyors in Singapore are required to conduct a gross error test of their GPS equipment at this reference point.