Pictures of the invisible

Episode number 5 of Series “The Shape of the world”.
In 1858 the picture of the world was transformed by the Frenchman Nadar who combined the new technologies of hot air ballooning and photography to produce the first reproducible “bird’s eye” view of the world. The technique of aerial photography has had extensive military use, but it has also enabled previously unmapped areas, such as the Himalayas and the Amazon to be accurately mapped. Now aerial mapping has been extended to photography from satellites and computer imaging of data, a process also used to convert radar “photography” of what lies beneath the surface of land and sea into a comprehensible form. Narrated by Patrick Stewart.