Category Archives: History

Ptolemy’s World of Climates

idrisi1 Ptolemy’s World of ClimatesArab geography and Christian cartography get their respective inspirations from the same sources but at different scales and manners. Under the Abbasid caliphate Greek, Persian, and Indian scriptures are translated. The latter allows Arab geographers to develop their knowledge and makes them access new geographic skills. Prior to that, they had only notions of cosmogony. Ptolemy provides the first documentation to Arabs and Christians. However Arabs modify some of Ptolemy’s work and do not always integrate Greek heritage as it is.

Y.K. Fall differentiates between Greek cartography and Ptolemy’s document. The first distinguishes between the Earth, represented as a flat disc, and its inhabited areas. Greek scholars think that the Earth is surrounded by the sea. Whereas Ptolemy holds the view that land surrounds the sea and that there is interpenetration between continental and maritime masses. He lays emphasis on cities and ports as being symbols of civilization. The primordial concept from the Ptolemyan geography that considerably holds sway over Christian sciences and most importantly Arab sciences is that of the division of the world into latitudes and climates.

In Ptolemy’s work, the world is divided into latitudes from the equator to the 45th parallel north. Beyond this line the subdivisions are organised according to climates. The latter corresponds to the best known parts of the world which appears essential to be deeply studied. The use of this theory – that is to say the division of the world into climates – varies according to geographers. However, they share a common knowledge of central climates, which is where the Islamic world plays its role.

The term climate, iklim in Arabic comes from the geek klima, which means inclination, i.e the one of the Earth towards the pole from the equator line. This idea involves another translation of klima that is region (of the earth sphere). The notion of climate refers to an area spreading in longitude from one and end to the other end of the inhabited world, lying in latitude between two parallels.

Climates bring together cities, mountains, water streams and minerals and are defined according to their astral contexts. Arab tradition establishes seven climates for the inhabited area of the earth. In the scriptures that attempt to describe the globe, the most significant theme is the one that deals with central climate that it is the fourth climate. This climate is located in Mesopotamia and represents a balance in everything.
In the adab (ancient rules and tradition of good behaviour) geography, we find this privileged theme of the fourth climate. Al Razi (Geographer of the 10th century) locates Spain in the same climate as Bagdad, exalting its wealth and advantages in order to justify the comparison with Iraq. Idrisi (geographer of the 12th century) always associates each country or city with a climate. Therefore we can argue that this tradition travels throughout history and geographic types.

Some disagree with this theory. They are those who work under an administration and prefer to interpret iklim as being a country brought together around a county town.

There are those who are inspired by another sense of the word originating from Persia. Keshwar describes the seven kingdoms of the world, of which six (India, China, Turcs, Rum, Africa, Arabia) are spread around the central kingdom of Persia. The number seven does not appear with Ptolemy but we find again this idea of a central climate prevailing over the others. The difference here is that the Persian climate is a politico-ethnic concept and no more a geodesic one.

Christian geographers divide the world into five climates or celestial zones. Each zone is determined by the yearly sun circumambulation inside the ecliptic. At the centre there is an uninhabitable zone. At each end we find a cold, boreal and austral and uninhabitable zone and in between lie two temperate zones. Christians were concerned by pragmatism and the supremacy of a zone over the other does not appear. However the idea of dividing the world into climates reveals the Ptolemyan influence within the cartographers.

If you have enjoyed all the exciting information in this article about geography and cartography, you will love everything else about GIS you will find at

By Morad Ouasti

The Biography of Abu Rayhan al-Biruni. A Forgotten Great Scholar

Abu Rayhan Al-Biruni was a great Persian Muslim scholar of the 10th and 11th centuries. Like many of the Muslim scholars, he believed that he could get closer to God if he understood his creation. Although his life and his contribution to science could be the focus of entire books, we will approach only the geographical aspect of his scientific work.

Lunar eclipse al Biruni 1024x721 The Biography of Abu Rayhan al Biruni. A Forgotten Great Scholar

Al-Biruni, is a Persian scholar who was born in 973 in Khwarazm, today known as Karakalpakstan (Uzbekistan). He studied under the famous astronomer and mathematician, Abu Nasr Mansur. By the age of 17 he was involved in scientific research. In 990 he determined the latitude of Kath (Uzbekistan) by observing the maximum altitude of the sun.

He wrote his Cartography which is about map projections. As well as describing his own projection of a hemisphere onto a plane. By the age of 22 he had studied a wide range of map projections and addressed them in treaties.

In 995 the rule by the Banu Iraq was overthrown in a coup. Al-Biruni fled at the outbreak of the civil war.

By the 4th June 1004 al-Biruni came back to his homeland. Abu’l Abbas Ma’mun became ruler and he provided important resources to al-Biruni’s scientific research.

Armed conflicts in the region interrupted the scientific work of Al-Biruni and made him leave Khwarazm around 1017.
Al-Biruni studied Indian literature, and translated many Sanskrit texts into Arabic. He also wrote treatises about Indian astronomy and mathematics. He was versed in astrology, astronomy, chronology, geography, grammar, mathematics, medicine, philosophy, religion, weights and measures.

He wrote his famous text, Shadows, around 1021. It is a precious legacy of the history of mathematics, astronomy, and physics. He is also the pioneer of what would be later known as polar coordinates.

Greek scientists, in particular Ptolemy, inspired Al-Biruni as for his conception of the spherical shape of the earth and its geographical components. In his al-Qānūn al-masūdī, he addressed the Greek astronomers’ theory of the earth and enhanced the debate of the distribution of land and sea with new knowledge and thinking.

In his Tahdīd he approaches climate change and stratigraphy. In India he interpreted the theories of the earth both of the Purānas (religious text about the history of the universe from creation to destruction) and of the Indian astronomers.

Al-Biruni made large contributions to geodesy and geography. He introduced techniques to measure the earth and distances based on triangulation. He claimed that the radius of the earth was 6339.6 km, by observing the height of a mountain in India. His Masudic canon reveals a table with the coordinates of six hundred places. Some of them were given by al-Khwarizmi (Persian scholar, 780-850).

Coming to the geographical organisation of the world, Al-Biruni accepted the Greek teaching of the seven climes, and also explained with deep precision the seven kešvars (Ancient Persians conceived the world as vast, round and surrounded by a high mountain) of traditional Persian geography and the seven dvīpas ( “peninsula, island” in Indian mythology) of the Indian Purānas.

Al-Biruni’s focus was mainly in the location of places relative to each other, their latitudes and longitudes, and the computation of their azimuths (angular measurement in a spherical coordinate system) of the qebla (direction to Mecca).

Al-Biruni did not meet problems for establishing local latitude. The longitude difference between two different places was his main obstacle. He managed to overcome it by assessing the longitudinal difference based on an amendment of the itinerary distance between two localities, using the latitude of each, and a determined value for the circumference of the earth. After establishing the longitudinal difference between any places of known latitude and Mecca has been determined, he managed to compute accurately the azimuth of the qebla.

Abu Rayhan al-Biruni died in 1048 in Ghazni (Afghanistan).

If you have enjoyed all the exciting information in this article about geography and cartography, you will love everything else about GIS you will find at

By Morad Ouasti

A History of Maps of Egypt

“This documentary reveals some very interesting facts about Ancient Egyptian maps, from antiquity through the times of the Arab explorers to the present times. Video is in Arabic with English subtitles, viewing is highly recommended”