Reference systems of maps and geographic information systems of Antarctica

The necessity for uniform reference systems for conventional maps (analogue) and geographic information systems (digital) is discussed. It is recommended that the following scales and projections are used for Antarctic maps: general maps at scales smaller than 1:1 000 000 should use a stereographic projection. Maps up to a scale of 1:1 000 000 should be compiled according to the specifications of the International Map of the World (IMW) 1:1 000 000. Ellipsoids are used as reference surfaces for the various map projections. Differences of the ellipsoidal parameters of the WGS72 and WGS84 systems have to be considered if accuracies better than 10 m are required. Geographic information systems may store data in vector or raster format and in geographic or in geodetic coordinates. For a raster format which is referred to the geographic (spheroidal) grid the term of ‘geographic raster’ is introduced, in contrast to the ‘geodetic raster’ which is referred to a plane cartesian coordinate system. The Institut für Angewandte Geodäsie (IfAG) is establishing the ‘Geocoded Information System Antarctica’ (GIA) using digital satellite image recordings. Internal storage of data in the GIA is in the form of the geodetic raster (and not by spheroidal coordinates). For the scale range 1:250 000 to 1:1 000 000 the size of the raster element is 60 m × 60 m. For smaller scales, satellite image data of a raster width of 240 m × 240 m are preferred.‘All cartographers' trouble began with the abolition of the flat-Earth theory ’