Scientists have unravelled the mystery of a nautical chart that had remained a mystery for almost two centuries

Researchers have now shown that the problem was not with the chart itself. The problem was that people were trying to read it in a way that differed from how real sailors read it.

This new study has proven that the 18th–early 19th-century Kachchi-Gujarati scroll was not merely a decorative curiosity, but a practical navigational tool. It helped sailors from western India navigate the Red Sea and the Gulf of Aden — one of the most challenging maritime regions between India, Arabia and the Horn of Africa.

The study has been published in the Journal of the Royal Asiatic Society.

What sort of map is this?

It is a long, narrow paper scroll from the maritime tradition of the Kachchh and Gujarat regions in western India. It depicts the southern part of the Red Sea and the Gulf of Aden – a route vital for trade, pilgrimage and maritime links between India, Arabia and East Africa.

The document entered the Royal Geographical Society’s collection in 1835. It was acquired by the British officer and traveller Alexander Burnes from a local pilot in Kachchh and donated to the Society. In the archives, the scroll was catalogued under a title such as ‘Indian map of the coast of Arabia and the Red Sea’.

The scroll was narrow – about 24.5 cm wide – but long – about 195 cm. This made it convenient to use on board: the map could be partially unrolled, revealing only the relevant section of the route, whilst the rest remained rolled up.

Why it remained misunderstood for nearly 200 years

European researchers long regarded the map as a ‘poor’ version of a European nautical chart. It did not live up to expectations: it did not look like a precise coordinate diagram, did not show the Red Sea and the Gulf of Aden in their familiar forms, and was not drawn up like a modern navigational chart.

Alexander Burnes, who sent the scroll to London, both admired and underestimated it. He described it as a rare example of nautical cartography, but also believed that it lacked latitude and longitude. Later, the map acquired a reputation for being ‘crude’ or primitive.

This new study effectively vindicates the document. The authors demonstrate that the chart was accurate not in the European mathematical sense, but in a practical one. It recorded the information an experienced seafarer needed: place names, directions of travel, landmarks, reefs, islands, coastlines and astronomical data.

This was not a map for a novice. It was not intended to ‘explain everything’ to someone who had never sailed these waters. It served as a reference guide for a seafarer already trained in the local navigational tradition.

On the scroll, researchers identified and deciphered around 66 place names written in Devanagari. Previously, many of these had remained unrecognised or had not been precisely linked to actual locations. The authors of the new study have established the coordinates for all these place names and improved their interpretation.

The map also contained astronomical data relating to the determination of latitude and the direction of travel. This was of critical importance to sailors: they were able to navigate by the stars, coastlines, islands and reefs, combining the information on the scroll with their own experience.

What the researchers found on the scroll

The map turned out to be far more detailed than previously thought. Researchers have identified more than 180 islands, reefs, coastal landmarks, religious buildings, flags, direction lines and key points along the coastline.

Of particular interest are the 29 rhumb lines — directions that helped navigators understand the general course of the coastline, routes across open water and, possibly, safe passages into and out of ports.

The map also depicts Islamic buildings – likely specific mosques or holy sites in the region. The flags may have indicated political and tax centres, which were important for trade and the control of sea routes.

Why the map looked ‘wrong’

Modern people are used to maps where space is represented mathematically: scale, grids, coordinates, and familiar coastlines. But this scroll worked differently.

It did not set out to be a universal map of the world. It was a memory aid. Its purpose was not to show the sea ‘as in a satellite image’, but to help an experienced sailor recall the required route, landmarks, hazards and directions.

That is precisely why its form might have seemed strange to Europeans. But for local navigators, it was practical: a narrow scroll was easy to store on a ship, easy to unroll in sections, and easy to use alongside oral tradition, celestial navigation and practical experience.

Why this discovery is important

The history of this map shows how easy it is to make a mistake when assessing someone else’s system of knowledge solely by one’s own standards.

For a long time, European scholars regarded the scroll as an ‘inaccurate map’. New research shows that this was not a mistake, but a different navigational logic. Sailors from Kachcha and Gujarat did not simply ‘roughly estimate’ the route – they used a complex system of practical knowledge that enabled them to navigate safely through the Red Sea and the Gulf of Aden.

This is also an important reminder: the history of navigation is not merely the history of European instruments, globes and coordinates. Before the spread of more abstract instrumental navigation in the Indian Ocean, there were effective traditional seafaring practices of their own.

Why this is not just an ‘old map’

This scroll is neither a museum piece nor a random curiosity. It is a record of living maritime practice.

It shows how seafarers linked India, Arabia, the Red Sea and the Horn of Africa. Such routes were vital for trade, exchange, pilgrimage and political ties. Goods, people, ideas and religious practices travelled along them.

This is precisely why deciphering the map is important not only for the history of cartography. It helps us to glimpse a whole world of maritime knowledge that has long remained in the shadow of European archival accounts.

Background

For centuries, the Red Sea and the Gulf of Aden have formed part of the most important maritime routes between the Indian Ocean, the Arabian Peninsula and East Africa. These waters are difficult to navigate: they contain reefs, islands, narrow passages, treacherous shores and significant seasonal winds.

For sailors who travelled these routes, a map was only part of their knowledge. Equally important were memory, experience, verbal instructions, knowledge of the stars, coastal landmarks and local place names.

A new decipherment shows that the ancient scroll recorded precisely such a system — no less complex than European navigation, but simply organised according to a different logic.

Source

Study: John P. Cooper and Kumail Rajani, “Kachchhi-Gujarati navigation in the Red Sea and Gulf of Aden in the eighteenth and nineteenth centuries: an intangible knowledge system, charted”, Journal of the Royal Asiatic Society, 2026.