Optical satellite images
Satellites with optical sensors generate images of the Earth over relatively large areas and are useful in the production of vegetation maps or to estimate specific vegetation parameters.
The sensors function in the optical part of wavelength spectrum, and include visible, near infrared and short-wave infrared wavelengths. These wavelengths are useful for distinguishing between forest types and other vegetation classes. Satellite sensors commonly used for detailed mapping include SPOT, Landsat, and Sentinel-2 with moderate resolution (pixel size 10 to 30 m).
Optical satellite data can be combined with laser data because the color information in optical satellite data can distinguish different vegetation types while laser data provides additional information about terrain or vegetation characteristics. For example, a current application with Sentinel-2 data – which acquires a new image over a given area ca every 3 days at northern latitudes, and has more bands in the “red edge” wavelength region – is to classify and map tree species.