Cartography has always been a significant sideline with the institution and, as with books, copies of all maps issued in Australia have to be placed on ''legal deposit'' at the library.

The cartography collection includes an estimated 1.5 million individual items Martin Woods, the NLA's curator of maps, says.

Exhibits for next year's exhibition will come from much further afield however. Library staff are working with a wide range of overseas institutions including the Vatican Library, the Bibliotheque Nationale de France and the British Library to secure the best of their collections for a brief trip Down Under.

Two items from the National Library collection that are likely to make the final cut for display are a pair of remarkable globes, one terrestrial and one celestial, dating back to 1825 and 1799 respectively.

The work of high-end British globe makers, John and William Cary, the pair were acquired in 2011.

Dr Woods, a man in love with his work, comes close to a state of rhapsody when describing the intricate marriage of craft and science required to produce such stunning artefacts from the age of exploration and discovery.

''The Carys were in business from 1790 to 1850,'' he said. ''The business ended with the retirement of the sons of the founders, John and William. John was the businessman and printer while William was the globe maker. Brittania ruled the waves and they had access to all the latest cartographic information.''

Manufacturing the globes, which were expensive status symbols intended for public and domestic display as much as utility objects, was a complex and time consuming business that required a knowledge of geometry, cartography and a high level of craftsmanship.

Expensive at the time, they are not cheap now with a pair similar to those in the library collection unlikely to leave much change from $100,000.

''Each globe has an internal frame made of pieces of bent wood,'' Dr Woods said. ''A paper mache case was then formed over the frame. Any bumps and hollows were then smoothed out using plaster of paris. The finished spheres are close to perfect and have balance weights inside, usually lead shot, so they will revert to a set position.''

Dr Woods said it wasn't until after World War II, when it was necessary to restore many historic globes that had been damaged in the conflict, that modern researchers became aware of just how sophisticated the construction techniques actually were.

Once the globe was finished ''gores'', elliptical slices of a world map based on the Mercator projection, were then pasted to the surface. In the case of the Cary globes the joins between the sections are so perfect as to be effectively invisible to the naked eye.

Each ''gore'' was printed in black and white and then hand-coloured by highly trained artists.

Once they had been applied the globes were then lacquered with at least three or four coats of gum resin. The finished result, in this instance mounted in a beautifully crafted and French-polished mahogany quadrant and tripod stand, presents an illusion of depth as a result of the combination of lacquering and hand colouring.

The terrestrial globe, the 1825 edition, is notable for information on voyages of exploration including those of Captain Cook.

''Besides the impressive stature, the globes are by the leading globe maker of the immediate post-Cook era,'' the acquisition report states. ''Cary's globe 'gores' were noted for their fine engraving, considered superior to other makers less concerned with cartographic correctness. The Australian cartography may be dated to the mid-1820s, with the name Australia given to the whole continent and some mapping of the land mass present''.

An adorable counterpoint in the library collection to the big globes, which are 53 centimetres in diameter, is a ''mini-me'' pocket globe also produced by the Cary brothers. Acquired in 2009 and protected inside a shagreen (dressed shark skin) case, this 1791 marvel is also notable for the quality of its workmanship and attention to detail.

The library's globe collection also includes a pair of 38 centimetre Cushee globes dating from 1731 (before Cook's voyages) and a pair of 46 centimetre Bardin globes dating from 1814.

Unfortunately the history of the library's Cary globes is not known. They were purchased from America and are unique in Australia.