Singapore legislation
Regulation 22
of Boundaries and Survey Maps (Conduct of Cadastral Surveys) Rules 2005
Regulation 22
Accuracy
A registered surveyor must conduct every cadastral survey according to established principles of survey and must attain the accuracy specified as follows:
the precision of every measured vector must be such that the standard deviations of its length and direction do not exceed 5 millimetres ± 5 ppm and ± 5 seconds, respectively;
wherever applicable, the position of every ISN marker adopted in the survey must have an error ellipse with its semi‑major axis not exceeding 0.020 metres;
the length of every traverse circuit must not exceed 2,500 metres;
the angular misclose must not exceed 10√n seconds where n is the number of traverse stations occupied in the traverse;
every traverse circuit must comprise a closed loop;
the fractional linear misclose of traverses must be better than 1:20,000; (g)every vector that is not checked internally must not exceed 50 metres in length and must be checked independently.