English: A map showing the location of the baseline for the trigonometrical survey of Moreton Bay , Queensland, led by Robert Dixon which began in 1839. The baseline was measured on what was named Normanby Plains , now known as Harrisville which is 20km south of Ipswich and lies near Warrill Creek. This survey led to the first accurate map of the region. (Datum: WGS 84)

Landmarks in the region, such as the two peaks shown, were selected as trig points to create a network of triangles. Triangulation of the network from the 3 mile baseline with the angles measured between the trig points was calculated using the law of sines and logarithm tables. The surveyors also employed celestial observations, including lunar distances , tying the survey to latitude and longitude and as check on accuracy. This control network provided a framework for larger scale surveys and maps.

Another baseline of seven miles was measured on Normanby Plains in the 1920s as part of the survey for army maps by the Australian Survey Corps. This triangulation was commanded by Captain Thomas Vance with the first topographical map published for Beenleigh in 1923.