Struve’s Geodetic Arc
In 2005 Struves Geodetic Arc was the first technical/scientific undertaking to be entered on the UNESCO World Heritage List.
The Geodetic Arc represents an enormous surveying accomplishment, comprising work which took 39 years to complete from 1816 to 1855 and was undertaken in order to finally establish the exact size and shape of the planet earth.
The project was undertaken through cooperation between the governments of Russia, Sweden and Norway. It was the first international scientific cooperation organised at national level in world history. Struve’s Geodetic Arc along the meridian was determined by employing a chain of measurements of angles over 2822 km from Ismail on the Black Sea to Fuglenes in Hammerfest. The measurement chain was formed by triangulation using triangles with sides measuring from 20 – 40 km. Measurements of angles was carried out at 265 main locations with 60 sub-locations divided along the meridian. In modern geography the arc or chain of triangles stretches across 10 different countries: Norway, Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Belarus, Moldavia and the Ukraine.
UNESCO’s resolution provides for the preservation of 34 points which are still intact from the time the original measurements were carried out. All the points have some sort of marking; a hole in the rock, an iron bolt, a collection of stones (originally a cairn marker) or an obelisk.
The Norwegian measurement points are:
1. The final point on the meridian.Column in Hammerfest.
2. The top of the mountain, Lille-Raipas (Una Raipasas) in Alta 286 above sea level
3. The top of the mountain, Luvddiidcohkka (Lodhiken) in Kautokeino.
4. The top of the mountain, Bealjasvarri/Muvravarri in Kautokeino .
The Russian astronomer and geodetic mathematician Friedrich Georg Wilhelm Struve (1793 – 1864) had overall responsibility for this comprehensive project. Based on measurements that were computed by surveyors travelling on foot between the survey points it was established that the equatorial radius of the earth was, 6,378,361 metres, which is just 224 metres longer than we can determine with today’s advanced measurement techniques.
