This map is a visual representation of the rainfall records kept in South Australia up to 1911, and shows Goyder's line of rainfall. The map is coloured to show areas that have similar rainfall with a scale of shades. The boundary of each area is shown by an isohyet, that is, a line connecting places having equal rainfall. There are two inset maps for the Northern Territory and an enlargement for the metropolitan area and adjacent ranges, showing water supply catchments.
The Commonwealtth Bureau of Meteorology was established in 1908 following the federation of the separate colonies to form the Commonwealth of Australia. Records which had been collected by the separate colonies over many years were transferred to the new Commonwealth Bureau, but state bureaus were still essential to the gathering of local data and weather forecasting.