defence. In 1947 a National Mapping Section in the Department of Interior was established and together with the Survey Corps commenced work on the 1954 Cabinet approved general purpose (national development and defence) national topographic map programme, initially the 'four-mile' map then soon after scale 1:250,000 maps (series R502). Army agreed that when not required for solely military purposes, Survey Corps units would be available to work in the Defence priority areas in the Government approved national geodetic survey and topographic mapping programmes. This programme involved control surveys by astronomical fixes, theodolite and chain triangulation and traverse by theodolite and electro-magnetic distance measurement and all aspects of map compilation from aerial photography, final cartography and map printing. The Corps' geodetic surveys were integrated with other Commonwealth and State Government surveys to create the NMC sponsored Australian Geodetic Datum 1966 (AGD66) and the associated Australian Map Grid 1966 (AMG66) of Australia and Papua New Guinea and the Australian Height Datum 1971 (AHD71). By 1968 the Corps had completed its commitment of about half of the 540 series R502 maps and it then embarked on the Defence priority part of the 1965 Cabinet endorsed national programme of general purpose scale 1:100,000 topographic maps. This programme required densification of the national geodetic and height survey networks with mapping quality control surveys of Cape York, Gulf of Carpentaria, northern Northern Territory and north-west Western Australia using mainly airborne electromagnetic distance measurement systems (Aerodist). The Corps completed its commitment of 862 of these maps in 1982. In areas of higher defence interest the Survey Corps replaced the series R502 1:250,000 maps with the military specification 1:250,000 Joint Operation Graphic (JOG) Ground and the companion Air version using materials from the 1:100,000 and Defence 1:50,000 mapping programmes and from other suitable sources. Units and command staff post-Second World War Army Headquarters Directorate of Survey – Army Headquarters Field Force Command – Senior Staff Officer and Survey Section Army Survey Regiment based at Bendigo, Victoria, formerly AHQ Survey Regiment and Southern Command Field Survey Section, AHQ Cartographic Unit, LHQ Cartographic Company and AHQ Cartographic Company 1st Field Survey Squadron based at Gaythorne and Enoggera Barracks Brisbane, Qld, formerly Northern Command Field Survey Section and Northern Command Field Survey Unit – Queensland, Territory Papua and New Guinea 1st Topographic Survey Squadron, now part of the Royal Australian Engineers, based at Enoggera Barracks in Brisbane, formed from 1st Field