AbstractMethods for fixing isolated points on to the national grid system, by observations of a few distances and angles, are discussed. There must always be one or two redundant measurements, to provide checks, but the desired positional accuracy for cadastral surveys can be obtained by semi-graphic methods or intelligent averaging of computed values, taking account of the relative probable errors of angles and distances. It is not necessary, in these simple situations, to use rigorous methods of adjustment under the principle of least squares.