Restoration of ancient French-era maps of Vietnam's seas - scientific evidence of sovereignty over seas and islands

Associate Professor, Dr. Dao Viet Ha at the Ancient Map Exhibition Area at the Oceanographic Museum

Valuable map documents about Vietnam's sea area

In over 100 years of development, along with research projects on the Vietnamese sea and the East Sea, the Institute of Oceanography has preserved many valuable books, magazines and maps. Among them, a rare set of documents on oceanography is also stored with 2,224 pieces of maps, nautical charts, and aerial photos of 739 maps (a map can have many pieces). The Institute's map archive is classified according to content including sea maps, nautical maps, bathymetric maps, East Sea maps, Vietnam maps and Vietnam geological maps. The oldest map was published in 1831, most of the sea maps before 1975 were published in France and some were issued by the US Navy. In addition, some maps of the northern coastal defense line of Vietnam (military maps) were published by the Vietnam People's Navy from before 1955 to 1976. Typically, the East Sea depth map warns of dangerous fishing areas in Hoang Sa and Truong Sa. The map of corals, continental shelf from the Gulf of Tonkin to Hoang Sa, Truong Sa, to the Gulf of Thailand and the Natouna overlap area near Indonesia was built from data from survey trips by the De Lanessan ship of the Indochina Oceanographic Institute in 1925 - 1929. In addition, the map of the coral islands of Thi Tu, Loai Ta, Subi in the Truong Sa archipelago east of Annam was drawn by British navigators from 1867-1868. In addition, the maps of Pattle Island in Hoang Sa are related to the planning plan for Hoang Sa Island during the French survey trip in 1937.

This set of map documents is of significant value for historical research on Hoang Sa, Truong Sa, Vietnam's sovereignty over the islands, serving the diplomatic struggle for the implementation of sovereignty. This is also a valuable set of documents serving the work of reference, comparing the changes in topography and geomorphology of Vietnam's coastal areas with current survey and mapping data. However, after a long storage period, most of the maps have seriously degraded due to changes in the physical condition of the paper, with the risk of rotting and damage. Therefore, the restoration, digitization and construction of a database of this source of documents is a necessary and urgent task to preserve and promote important scientific and historical values as well as serve the work of promoting sovereignty over the islands through scientific and historical evidence.

Based on the above facts, scientists of the Institute of Oceanography proposed and were approved by VAST to carry out the task of "Restoring and building a database of ancient French maps of the Vietnam Sea and the East Sea" (code: NVKH17.00/23-23).

Research restoration and promotion

Within the framework of the task, the team restored 415 maps of Vietnam and the East Sea published in 1831-1948 by using the method of backfilling, reinforcing both sides of the map with Japanese do paper and Vietnamese do paper according to the procedures of the State Archives Department at the National Archives Center IV in Da Lat. The team digitized 739 maps and stored them in PDF and PNG formats with a resolution of 300 dpi, sharp and without information deviation from the original maps. Of which, QR codes were created for 52 maps to serve the thematic room. The research team successfully created an Excel database of 2,224 map sheets (of 739 maps) with 25 information fields (map name, year of publication, place of publication, scale, coordinate system, type of geological or depth map, storage cabinet, information recorded on the map).

Four pieces of the bathymetric map of the South China Sea (Carte Bathymétrique de la Mer de Chine Méridionale) before restoration

Depth map of the South China Sea (Carte Bathymétrique de la Mer de Chine Méridionale) after restoration

*Vietnamese information: Map of Paracel Islands, Paracel Islands, 1939

The map depicts the morphology of the islands and the tidal levels around the islands of Hoang Sa, Phu Lam and Huu Nhat in the Hoang Sa Archipelago. The map was drawn from data of the Indochina Hydrographic Survey Team in 1938, under the command of Mr. P. Couillault - hydrographic engineer and Mr. J. Aubertin - captain of the Corvette.

In the report of Dr. Raoul Serène - Former Director of the Indochina Institute of Oceanography - in 1953, this map was related to the survey trips to prepare for the construction of lighthouses, TFS radio stations and meteorological stations on the Paracel Islands in 1938 according to Decree 3282 signed by Governor-General of Indochina Joseph-Jules Brévié.

Photos, QR codes and map information of Hoang Sa island, Hoang Sa Archipelago in 1939 after digitization

In particular, the launch of the map exhibition area with the theme "Presence in the East Sea" includes 18 maps, designed and arranged to ensure scientific and aesthetic standards with three main topics including: Vietnam's Hoang Sa - Truong Sa imprint in ancient documents, Vietnam's journey of exercising sovereignty over the two archipelagos of Hoang Sa - Truong Sa, Sea and islands with economy - society. The exhibition area has been opened to serve visitors, effectively carrying out the task of propagating Vietnam's sovereignty over seas and islands in the East Sea.

Some images of the ancient map exhibition area "Presence in the East Sea" at the Oceanographic Museum

Assoc. Prof. Dr. Dao Viet Ha shared: The research team has made great efforts to complete a large amount of work assigned. However, due to limited implementation time, some contents such as digitization and creation of a lookup database are only performed on Excel software. In order to effectively manage and exploit the digital information source of this map set, the group of authors wishes to continue to take the next step of building an ancient map database management software to effectively serve the lookup and exploitation work. Another product of the task is the book "Vietnam's seas and islands in ancient map documents", about 100 pages, introducing a number of maps of Vietnam's seas and islands in the East Sea that have been compiled by the project manager to propagate and promote the sovereignty of seas and islands. Hopefully, the book will soon be published and will be a valuable reference document welcomed by the scientific community.

Translated by Quoc Khanh
Link to Vietnamese version