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Satellite imagery has been used extensively in open-source investigative research: from monitoring global deforestation to documenting mass demolitions in Gaza.

When we view satellite images on platforms like Google Earth, the world looks very similar to how it does with the naked eye – for example, if you were looking down at the earth from an aeroplane window.

However, satellite images can also reveal things that humans can’t see. A common example of this kind of imaging is night vision, which uses infrared light to illuminate a scene that’s not visible to the naked eye. In satellite imaging, images made using additional types of light are known as multispectral images.

Multispectral satellite images can reveal useful information about the world, such as the presence and quality of water, types of vegetation, soil health and more. In this guide, we will explain the basics of how multispectral satellite imaging works, apply it to case studies relating to mining and deforestation, and review open-source tools and resources for using these techniques in practice.