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Release peace: the magazine

Release peace: the magazine

Analysis & Background Stories on International Affairs

How to Measure the Shape of the Earth? The Geodetic Arc

Article by: Tatiana Sondej

Photo credit: Gerd Johanne Valen

Mapping the Meridian

How would one go about measuring the shape and size of the Earth? This was the question at the heart of Friedrich Georg Wilhelm Struve’s work in the early 1800s. Struve was a renowned astronomer of German descent – he made an outstanding contribution to the human understanding of the world when he successfully measured a large segment of the meridian, a line of longitude commonly used for astronomical observations. His measurements combined together to create the Struve Geodetic Arc which spans from Fuglenæs in frosty Norway to Staro-Nekrasovka in Estonia, covering an expanse of 10 countries and over 2,820km of land (and the Black Sea).

Today, the Struve Arc is often associated with Norway’s Meridian Column which stands as a commemoration of Struve’s breakthrough study. The project required a great deal of international and cross-border collaboration. The Struve Arc is well-renowned for its distinguished universal value for Earth scientists and astronomers, as well as its historical significance to the human understanding of our planet.

What is the Struve Geodetic Arc?

As for the development of the Struve Arc, the process took place between 1816 and 1855. Struve calculated long chains made up of triangles to create the structure, and this was the first accurate measurement to be made of a noteworthy portion of the meridian. The system used for measurements was referred to as ‘triangulation’. Measures were completed on foot through rough and unpaved terrain – it was highly strenuous work for the team who moved their own equipment and went to great lengths to establish the station points. Struve’s discovery was crucial to the development of earth sciences, and an incredibly important step towards establishing the precise shape and size of the planet.

Spanning Across Countries

At the outset, the arc was composed of 258 main triangles and 265 station points – the points can be found in 10 countries, including Sweden, Finland, Estonia and the Republic of Moldova. Many of the station points can be visited – they are marked with drilled holes, cross-shaped carvings, and sometimes monumental structures such as the Tartu Observatory (Estonia), or the Meridian Column (Norway). As of July 2005, 34 points have been included on the UNESCO World Heritage List. UNESCO recognises the Struve Arc’s prestige as a pioneering scientific achievement and aims to promote scientific heritage and its role in forming our worldview.

The Struve Expedition

In the Nordics, a total of 10 Struve Arc points can be found, 4 of which are in Sweden and 6 in Finland. A number of the selected points are found specifically within the HaparandaTornio area, which prides itself on being home to 6 of the station points selected for the World Heritage List. Known within the region for their great historical importance, the arc points also provide outstanding views of the surrounding areas. Visitors are encouraged to expand their knowledge of historical heritage while partaking in a relaxing hike.

Fancy Paying a Visit?

In Sweden, the four station points are Pullinki in Övertorneå, Perävaara in Haparanda, Tynnyrilaki and Jupukka. They are all found in the Swedish part of Tornedalen, a geographical area rich in culture and pristine nature. Norrbotten’s County Administration and County Board are currently underway with projects to increase public knowledge of World Heritage sites right at their doorsteps. All the points are currently open as visitor sites, making for remarkable outdoor excursions – the station in Pullinki is also located next to a skiing facility, which HaparandaTornio advertises as the perfect winter getaway.

Three sites are located in Finland’s part of Tornedalen. These stations are Aavasaksa, Stuorrahanoaivi, and Nedertorneå Church (otherwise known as the Church of Alatornio). The Nedertorneå Church is an especially wonderful place to visit. The structure dates back to the Middle Ages and is said to have been built in 1316. It is of great religious significance in the Nordics, having been visited by the Archbishop of Uppsala, Nikolaus Hemming in 1346. However, the significance of the church lies not only in piety but also in its rich history as a point of measurement for the Struve Geodetic Arc.

Protecting the Arc

Each party involved provides legal protection to their respective arc points as required and upkeeps the management of the stations in a valiant effort to safeguard cultural heritage. Some points are protected under national geodetic laws, as well as laws for the preservation of cultural heritage sites. The responsibility usually lies in the hands of each country’s national mapping authority. Spreading knowledge of the Struve Geodetic Arc is equally important, and greater awareness is promoted via several means. The involved countries have used educational media (movies, articles, and leaflets) to increase knowledge in schools. They oversaw the restoration of geodetic materials and prepared exhibitions for a more interactive approach. The Baltic countries promoted the Struve Arc through the production of stamps and envelopes, and some even minted coins in commemoration of the great achievement.

A Monument to Scientific Collaboration and Diplomacy

The Struve Geodetic Arc not only acts as a scientific milestone but also holds immense historical and cultural significance. HaparandaTornio takes pride in its position at the northernmost point of the arc and strives to spread the word of the cultural heritage nestled within its terrain. Those visiting HaparandaTornio can even see the original surveying instruments used by Struve’s team during their expedition. The Struve Arc stands to remind us of the remarkable achievements that can be reached through joint efforts to advance our knowledge and understanding of the world.

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