Tuesday, March 02, 2021

Mapping a Landslide

In February more than 200 people were killed in the Himalayas when a landslide on India's second highest peak caused a flash flood which swept away villages and two hydro-electric projects. Such large landslides are rare at this time of year, leading climate scientists to warn of the potential for ever increasing numbers of deadly landslides in the Himalayas as the planet continues to warm.

Detailed satellite imagery can help scientists to more clearly understand the causes and consequences of large landslides. Reuters has used high resolution satellite imagery of Raunthi from before and after the landslide to map the extent of the destruction caused. In Disaster in the Himalayas Reuters has mapped Planet Labs satellite imagery on top of a Digital Elevation Model to map the steep face of Raunthi before and after the devastating landslide. 

In the article Reuters also uses photos and satellite & aerial imagery to document the landslide, the extent of the flash flooding and the damage caused to the local villages, bridges and dams.

Pratik Yadev has also used satellite imagery to provide before and after maps of the Raunthi landslide. His Swipe Between Maps visualization uses Sentinel-2 satellite imagery with Mapbox's 3D terrain view to show Raunthi before and after the February landslide. Two 3D aerial imagery maps are placed side-by-side on Pratik's visualization allowing the user to easily compare the before and after imagery by swiping between the two maps.

The two maps are synchronized together which means that you can explore the before and after imagery in detail by zooming in and rotating the 3D map. As you zoom or pan in one map the other map automatically zooms and pans to stay centered on the same location and view.

No comments: