In the field Hedin documented his observations in several different ways. He kept his note books with texts and figures and continuously kept his attention focused on the route-map. At camp he wrote one long letter after another to his home in Stockholm, which constituted his diaries. During the first expedition he lost his camera-equipment during the ill-fated, but for building his fame successful, so called “death march” through the Western Taklamakan desert. During the next two expeditions taking photos was an important part of his work, and he was a careful as well as gifted photographer. On the one hand the glass-negatives exposed, developed and cautiously transported by mules, camels or yaks were meant to complement his written notes and add to his memory of landscapes and people. On the other hand they would crucially add value and importance to his publications; scientific weight to his scientific ones and attraction to his travelogues.
After losing his camera in the desert in 1895 Hedin had to solely turn to his sketch-book for such purposes. Such books had always been with him. The first rather naïve attempts to document what he experienced had been made already after arriving by boat in Åbo, Finland in 1885 on his way to Baku. Sketching and making watercolors was then in no way new to him, though he had had but little formal training. And his father must have been a source for great inspiration. He was the City architect and could produce superbly colored drawings of houses and their facades.
Sven Hedin soon put a great effort into developing his skills with pencils and later on with brushes, and his Persian travelogue contains many illustrations by his hand, as will his following books. After the momentous loss of his camera in 1895 he was forced to fully rely on on his sketch-book, and many of the finest works by his hand belong to the latter part of that expedition. A favorite pastime of his was drawing portraits. Asking a model to sit down in front of him, catching his or her features was a source of pure relaxation. Another favorite motive was discovered in his Bactrian camels, drawing their stubborn appearance and characteristic “hairstyles”.
Hedin argued that the faithful representation of what was in front him was the only reason for him to make a drawing. Later in life he did not always follow that creed. But it tallies well with the technique he made into a cartographic one during his third, Persian and Tibetan expedition. He drew exact panoramas of the landscape taking the bearings of every visible feature of the surrounding landscape, in particular all peaks. These panoramas were found to be so exact that an additional, parallel set of maps could be constructed from them.