Poles of Inaccessibility (PIA), a concept that has raised the interest of explorers. The results are in this table. For the Eurasian pole of inaccessibility (EPIA, located in the figure), the results reveal a misplacement in previous calculations ranging from 156 to 435 km. Though in general there is only one pole for a given coastline, the present calculations show that, within the error inherent to the definition of the coastline, two locations candidate for EPIA, one equidistant from Gulf of Ob, Gulf of Bengal, and Arabian Sea, and the other equidistant from Gulf of Ob, Gulf of Bengal, and Gulf of Bohai, both poles being located in the north westernmost Chinese province of Xinjiang. The distance to the sea at these locations is 2510 and 2514 km respectively, about 120 km closer than popularly thought.
Details in this publication by Garcia-Castellanos & Lombardo, 2007. Source of the C code and Linux scripts to test/reproduce the results are available here.
The term is also used to refer to the place on Earth that is furthest from any ocean (Eurasian Pole of Inaccessibility, hereafter referred as EPIA), located in central Asia. Explorers such as Cable & French (1944, p. 94) refer to the region of the Dsungarei Desert as “the spot of the globe which is farthest removed from any sea or ocean”.
In recent years, as expeditions have been conducted to document the PIA of Antarctica (19th Jan. 2007) and Eurasia (Crane & Crane, 1987), there has been an increasing interest in the subject, while academic documentation remains very scarce. Although graphical methods to calculate such poles are long known, as digital coastlines and geographical databases become gradually available, the necessity for a numerical method is growing.
In this paper, a simple method is proposed and used to calculate the PIA’s associated to the largest landmasses on Earth. The application of this method reveals an error of between 156 and 435 km in the location popularly regarded as the EPIA (Crane & Crane, 1986).
The two candidate poles found in this paper reduce the Earth’s maximum distance to the coast by more than 130 km, and modify the location of the PIA by 435 km (EPIA1) and 156 km (EPIA2) relative to previous calculations. In the case of EPIA1, also one of the CSP changes from the Gulf of Bohai (East China) to the Arabian Sea. These results question the only documented attempt to explore the EPIA by two explorers in 1986 (Crane & Crane, 1987).
EPIA1 lies near Kokirqin Shan Mountain (3698 m), at an area of high relief and difficult access at >2000 m above sea level, close to the Chinese borders with Kazakhstan and Kyrgyzstan. EPIA2 lies at 710 m altitude, 174 km NNE of Ürümqi.
Besides being far from the oceans, both poles are in the largest endorheic basin in the world, meaning there is no fluvial connection to the sea (Cable & French, 1944). This is partially the result of low precipitation values of 200-350 mm/yr as a result of continentality. Both factors have probably enhanced the historical isolation of this region acting as a natural border between the Chinese and the Western civilizations. Its faint presence in history is mostly linked to the relative vicinity (a few hundred km) of the ancient Silk Road. Unsurprisingly, the region is among the less populated areas of the world, and the ethnic group longest rooted in the region, the Uyghur, is linguistically included in the Turkic family and interfingers with population speaking Chinese languages.
The spot on planet Earth that is most distant from land (Pole of Inaccessibility of the Pacific Ocean, or Point Nemo) is at 48°52.6′S, 123°23.6′W, 2690 ± 2 km far from the coasts of Motu Nui (Easter Island), Maher Island (Anctartica), and Ducie Island (Pitcairn Islands). PIA’s calculated for other continental masses with the same technique are listed in Table 1.