Our boundaries move

Boundaries are commonly regarded as stationary. Depending on the terrain, however, they are subject to climatological changes and natural phenomena and may thus change their course.

Glaciers

topographic map
National border on the topographic map

The water divides above 3'500 metres traversing perpetual snowfields and glaciers have shifted during the past few decades, partly due to melting glaciers. The topographic map (above) and aerial photograph (below) show the border between Switzerland and Italy at the Furggsattel in Zermatt. The plus signs depict the border in 1940 and the new course is shown in red.

Aerial image of the national border
Aerial image depicting the identical border section

The graphic representation illustrates how the courses of boundaries around Zermatt are influenced by melting glaciers. From 1940 to 2000, the height of the glacier has decreased and the water divide now follows the rocks. This decrease causes a shift in the boundary of about 100 to 150 m.

Graphic representation
Graphic representation of how a glacier melts

Only approx. 40 km of the water divides between Switzerland and Italy (total length 578 km) traverse snow fields or glaciers. There are no snow fields or glaciers along the rest of the alpine borders between Switzerland and France and Switzerland and Austria which could result in any modifications. The entire border passes across solid terrain.

From the surveyor's point of view, these border changes are attributable to natural phenomena which have to be taken into account in order to guarantee an accurate revision and update of our topographic and cartographic products. However, it is not possible to carry out new surveys every few years, so such updates are only carried out as the need arises.

Rivers and streams

The Inn River marks the border between Austria and Switzerland
The Inn River marks the border between Austria and Switzerland

The border between the canton of Geneva and France has a total length of 103 kilometres, 50 of which pass through the middle of rivers. Over time, and as the result flooding, these rivers have also changed their course. Surveys show that in various places these border changes involve several metres, some of which are private property.

The same situation applies to the Doubs River, which forms the border between France and the cantons of Neuchâtel and Jura. As long as these rivers are not contained within channels, the borders will follow their natural course. Here again, nature decides and we can only accept these natural changes.


Federal Office of Topography swisstopo Seftigenstrasse 264
P.O. Box
3084 Wabern
Tel.
+41 58 469 01 11

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Relevant authority

Geodesy and Federal Directorate of Cadastral Surveying
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Print contact

Federal Office of Topography swisstopo

Seftigenstrasse 264
P.O. Box
3084 Wabern

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