In today’s TPI Tuesday, we present a case where a large agricultural activity took place, and many trees and bushes were removed. This type of activity often poses a threat to the pipelines due to the use of excavators, and because it can lead to soil erosion, and hence pipeline operators should be aware of these activities.
The upper image is an image from the field investigation, the image on the left shows the detection of the activity using the Sentinel-1 satellites, and the image on the right shows the detection of the activity using a Sentinel-2 widely-used vegetation index, the NDVI (Normalized Difference Vegetation Index). 🌳
NDVI uses the NIR and the Red bands, it’s calculated as NDVI=(NIR-Red / NIR+Red) and the values range from -1 to +1. It detects and quantifies the presence of vegetation, where the high values indicate the presence of green and healthy vegetation, and low values, the presence of bare soil, urban area, and water. This is because the healthy vegetation reflects the NIR light and absorbs the red light, and vice versa.
Interesting fact: The human eye can’t see the NIR light, so this is where the beauty of the optical remote sensing techniques arises! 😎