Optical Satellite Imagery
Optical satellite sensors regularly generate images of the Earth, providing valuable data for vegetation classification and forest type analysis.
By combining optical data with laser data, the information is complemented with details about terrain and vegetation characteristics. Laser data is obtained by sending laser pulses from a sensor—typically mounted on an aircraft, drone, or tripod—towards the ground or objects. Satellites with optical sensors generate images of the Earth over relatively large areas and are useful for producing vegetation maps or estimating specific vegetation parameters.
The sensors operate in the optical part of the wavelength spectrum, including visible, near-infrared, and shortwave 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 colour information in optical data helps distinguish different vegetation types, while laser data provides complementary information about terrain and vegetation structure. A current example is the use of Sentinel-2 satellite data for tree species classification. Sentinel-2 captures a new image of an area approximately every three days and includes additional information in the so-called “red-edge” wavelengths.