Journey through time – aerial images: 40 years of change in Switzerland
The SWISSIMAGE orthophoto mosaic produced using aerial images is now also available for 1985 through 1990. The “Journey through time – aerial images” online tool makes it possible to gain a complete view of Switzerland from 1979 to the present. The changes which can be seen and analysed using the swisstopo product are fascinating.
1979 was an eventful year for Switzerland. The Jura became a sovereign canton, the Gösgen nuclear power plant went live and “YMCA” by the Village People topped the charts. Since then, four decades have passed and the country has been transformed. This change is most obvious when you look at the country’s surface: towns have grown, agricultural land has disappeared, highways have been built and shopping centres have shot up everywhere.
“Journey through time – aerial images”, made up of orthophoto mosaics, provides a view of Switzerland over time. It covers the period from 1979 to today. The former gap between 1985 and 1990 has now been filled, further increasing the value of this product for science, politics and the interested public.
What is an orthophoto mosaic?
The photo data in “Journey through time – aerial images” comprises orthophoto mosaics. swisstopo staff have combined aerial photos into a whole to depict all of Switzerland. The borders between individual aerial photos or aerial photo strips are hardly recognisable since they were geometrically rectified in advance and combined into a colour-matched mosaic. They can be viewed seamlessly in their corrected and standardised alignment. The result could be called a “selfie” of Switzerland.
As snapshots of the earth's surface, orthophoto mosaics are an exciting addition to topographic maps as part of research. They show innumerable details which do not find their way onto the map image; in addition, the time at which the individual images were taken can be clearly determined. Topographic maps in turn help with interpreting orthophoto mosaics and go further back in time - to the year 1845.
Neuchâtel: a growing city, a shrinking lake
The city of Neuchâtel provides an example of the opportunities for observing space offered by “Journey through time – aerial images”. Like most Swiss cities, it has grown a lot over the last forty years. What is special about Neuchâtel though is that it did not just turn forests, fields and pastures into new neighbourhoods: The city also grew out into the lake.
Even during the 19th century, Neuchâtel spread by taking advantage of the shallow depth of the lake near the shore. Precious land could be gained using landfill: the city's special location between the Chaumont mountain ridge and Lake Neuchâtel made it attractive for expanding the neighbourhoods near the port and city centre at the expense of the lake. For example, the La Maladière football stadium and the Notre-Dame de l'Assomption church, famous for its red colour, are located in urban areas which were wrested from the lake.
Land gained for the highway tunnel
The latest chapter of the Neuchâtel lake landfill began in the 1970s. For centuries the city, which is virtually trapped between the lake and the mountain ridge, had been a bottleneck for regional and transit traffic. This situation worsened when, in the 1960s, the discussion about transformation of national road 5 into highway 5 began. The highway which now runs from Yverdon-les-Bains to Solothurn threatened to flood Neuchâtel’s city centre with cars.
The solution was to tunnel under the city from Serrières to Monruz - a proposal passed by voters in 1974. Construction work on the Tunnel de Neuchâtel lasted almost two decades before it was opened to traffic in 1993.
“Journey through time – aerial images” shows just how much the tunnelling changed the cityscape of Neuchâtel. The underground solution to the traffic problem led to new landfill by the lakeside. This was necessary to create the space at the two entrance portals to the tunnel needed by the motorway and the roads leading to the city centre. Rows of houses which were previously only a stone's throw away from the lake shore are now separated from the water by up to 150 metres of land. For the city, however, despite these specific disadvantages, the tunnel represented a sustainable solution to the transport issue.
“Journey through time – aerial images”: knowledge about Switzerland
The example of Neuchâtel shows the possibilities offered by “Journey through time – aerial images”. It makes the changes on the earth's surface visible and documents them with a high level of accuracy. “Journey through time – aerial images” thus creates an interface between the spatial and temporal dimensions of Switzerland. The product therefore offers countless possibilities for science, administration, politics and the interested public,: if you want to analyse spatial changes, immerse yourself in the landscape memories of the Swiss Confederation or wander through Switzerland’s spaces and eras out of pure curiosity, aerial photographs are the ideal tool for you.
Links
Federal Office of Topography swisstopo
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