Vegetation Health Index (VHI)

Updated on 05/09/2025

The map shows the current status of vegetation health as observed by satellites (Vegetation Health Index, "swissEO VHI"). This index also evaluates the climatic conditions, in addition to vegetation condition. The VHI base map has a high spatial resolution and provides information for every 10x10 meter area with vegetation. 

The current status is compared with similar values from the climate reference period 1991–2020. If plants wilt or discolour prematurely and temperatures are at the same time above average, the VHI value drops. A low VHI value indicates vegetation stress, for example during a dry period or in the event of disease infestation. The lower the VHI value, the higher the stress and the greater the potential damage to the vegetation.

Note: The VHI is a relative measure that is only meaningful if similar conditions are compared. For example, it is not meaningful for an agricultural plot on which different crops are grown each year. Managed forest from which timber has been extracted or storm damages may also show a comparatively low or dry value, as less biomass is present; the remaining trees may be just as healthy as in the climate reference period.

Since the satellites do not image the whole of Switzerland every day and clouds can also cause a lack of information, there are gaps in the data. The VHI for each grid cell is composed of the most recent data from the last seven days.

Data basis:

    • Current vegetation values: These are based on the product "swissEO S2-SR", which is produced from the optical Sentinel-2 satellite data from the European Space Agency (ESA). 
    • Vegetation values for the 1991-2020 climate reference period: These are derived from data from the Landsat program of the US Federal Space Agency and Flight Science (NASA). 
    • Temperature data (current and climate reference period 1991-2020) for the land surfaces: The data from the Meteosat satellites are provided by MeteoSwiss as part of the EUMETSAT CM SAF project of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT). 
;