A History of the Nigerian Triangulation System.

Daniels, Y. M (1973)

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This work does not attempt to develop either new methods of adjustments or computational produces, but to erotically look at the reduction of observed data to the reference ellipsoid and adjustment proces s. Its main objective therefore is to discuss the history of the Nigerian triangulation system and to consider the results of the adjusted values of the angles of some chains with those obtained by method of least squares adjustments, to consider the compu tation of geodetic coordinates and corrections to base measurements. The writer has found out that the Nigerian Triangulation Network started by 1914 in a piecemeal manner. Two separate parties were established to work in the then Southern and Northern Nig eria respectively. The separate triangulation chains thus established were later tried together. Hence the axiom of working from the whole to part was not applied. It was also discovered that the values of some of the horizontal angles adjusted by least sq uares differed from the originally adjusted values by less than 0.36 seconds. The azimuth of lines and hence computation of geodetic coordinates working with either values differ by 0.125 second. The appropriate corrections were however applied to the Base measurements. It is however recommended that the lengths of the basses should be ascertained by re - measuring them with an electronic measuring instrument in order to compare the values obtained with those obtained with the use of invar tape.