Vegetation Cover Condition Atlas
Satellite surveillance photos provide all kinds of information on the surface of the Earth. These photos help to determine not only such surface qualities as relief, urban territories and water ponds, but also more detailed and specialised data, which can be used for various purposes.
The principle of satellite surveillance is based on using different sensors on a satellite to measure electromagnetic waves coming from the surface of the Earth.
Electromagnetic radiation spectrum (based on NOAA)
The specific wavelength range is used depending on the analysed parameter (amount of moisture in the atmosphere, air temperature, etc.).
Using satellite measurements helps to define the type, distribution, intensity and condition of the vegetation cover. This involves using vegetation condition indices.
One of the first indices is the NDVI – Normalised Difference Vegetation Index – is calculated on global scale since 1981 using NOAA polar satellite imagery. The index is determined using the difference between the near infrared spectrum (NIR) and visible spectrum (VIS) (formula):
NDVI = (NIR-VIS) / (NIR+VIS)
The index fluctuates between -1 and +1:
<0 value – water surface
~0 value – surface without vegetation
0> value – vegetation cover
Larger index value means lusher vegetation and its better condition.
The VEGETATION COVER CONDITION ATLAS features the vegetation condition in the eastern part of the Baltic Sea region of 2010-2015 (May-June, 18-39 calendar week).
The size of the cells in the pictures is 16 x 16 km and the data timing step is 1 week.