Change Detection
Long-term datasets of satellite data are very useful in ongoing studies, particularly in the field of Change Detection. This data allows scientists to examine an area over a period of time, and see what changes (if any) are indicated, and determine the cause. Not only are the data of use in studying the past, but they can be used to forecast future changes based on past trends. Deforestation, Polar ice loss and Climate Change studies all make use of satellite data to monitor their particular fields. The rate and extent of forest loss and ice melt can be tracked, as well as overall trends of change in our world's climate. ESA has developed a large archive of this data from their satellites, particularly the two ERS missions and Envisat. Combined, the three satellites acquired data over the Earth for a period of 31 years. And from 2014 the Sentinel satellites will add to this archive with new imagery. Beyond static comparisons of images acquired over the duration of the mission, methods have been developed to merge these images. They can be combined into one "multi-temporal" image that highlights the changes in a location over a period of time.
Latest Change Detection Events
Crimean Bridge, Crimea23 January 2020 - The Crimean Bridge is shown in this Copernicus Sentinel-2 image comparison. The images show the bridge before and after it was engineered to add a rail line. 
Valencia, Spain29 August 2019 - The city of Valencia, in Spain, is featured in this satellite image comparison. Landsat-7 and Copernicus Sentinel-2 images were used to show how this port city has developed since 2000. 
Easter Island17 April 2019 - Easter Island is featured in this Copernicus Sentinel-2 image comparison. The island is depicted in natural and false colour imagery in order to demonstrate the multispectral capabilities of the Sentinel-2 mission. 
Mont Saint-Michel, France15 April 2019 - Mont Saint-Michel in France is featured in this Sentinel-2 image comparison. The images demonstrate the multispectral capabilities of Sentinel-2, showing natural and false-colour views of the location. 
Icebergs A-68 and B-46 in Antarctica14 December 2018 - Proba-V data was used to track the evolution of the A-68 and B-46 icebergs in the Antarctic Sea. The large icebergs broke off from the Larsen C ice shelf and Pine Island Glacier, respectively, in 2017 and 2018. 
Havana, Cuba31 October 2018 - Havana, the capital and largest city of Cuba, is featured in this Copernicus Sentinel image comparison. Sentinel-1, -2, and -3 imagery are used to obtain different views of the city and island, demonstrating the variety in how these satellites observe the Earth. 
Casablanca, Morocco18 October 2018 - This weeks image comparison focuses on the city of Casablanca, Morocco. Landsat 5 and 8 imagery have been used to highlight the changes in urbanisation during the last 13 years. 
Fires in Pisa, Italy04 October 2018 - Hundreds of people have been affected by fires in the hills of Tuscany since 24 September. These image comparisons from Landsat 8 and Sentinel-2 show the situation at Pisa, using natural and false colour imagery to detect the affected areas. |
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