Observations for
VCI values for the current month:

Vegetation Condition Index

This map shows the actual situation of the vegetation as reflected by the Vegetation Condition Index (VCI).

The Vegetation Condition Index (VCI) compares the current NDVI to the range of values observed in the same period in previous years. The VCI is expressed in % and gives an idea where the observed value is situated between the extreme values (minimum and maximum) in the previous years. Lower and higher values indicate bad and good vegetation state conditions, respectively.

It is possible to visualize the VCI for the full area or for the agricultural area only. Select a variable in menu>analysis.

Tabel 1: Interpretation of the Vegetation Condition index (VCI)

Legend of the VCI

This map was developed by the Instituto de Investigaciones Agropecuarias (INIA).

Logo INIA

How is the VCI calculated?

The VCI is calculated as:

VCI

Where NDVI is the minimum and maximum Normalized Difference Vegetation Index observed during the same time period of 16 days.

The NDVI is calculated as:

NDVI

Where VIS is the spectral reflectance in the visible region (red) expressed as ratio (reflectance/incoming) and NIR is the reflectance in the near infrared region (reflectance/incoming).

The figure below illustrates the calculation of the NDVI:

NDVI

Figure 1: Example of NDVI calculation

What is the interaction between the vegetation and the spectral regions NIR and VIS?

Plants absorb and reflect particular regions of the light spectrum. Large part of the VIS is absorbed by plants and used in the photosynthesis process. Large part of the NIR is reflected by plants because it cannot be used in the photosynthetic process. When plants are in bad condition there is a change in the absorbance and reflectance of VIS and NIR.

Dataset Documentation

Data
16-day average estimates on a 1km lat/lon grid dataset
Data Source
United States Geological Survey, Land Processes Distributed Active Archive Center, Moderate Resolution Imaging Spectroradiometer USGS LandDAAC MODIS
Note:There is typically a 12- to 16-day delay between the end of the observation period for the latest data and the date when those data are received and displayed on this page.

Helpdesks

Contact mwar_lac@unesco.org with any technical questions or problems with this Map Room, for example, the forecasts not displaying or updating properly.

Instructions

The interface provides users with the ability to make graphs. The interface provides a contextual perspective of recent MODIS images by displaying an interactive map of the Vegetation Condition Index (VCI). Time series analyses of VCI are generated based on user-selected parameters.

Isolating a certain region of interest can be accomplished by clicking and dragging a rectangle across that region. The map will zoom to that area to allow for more precise variable. Any zoom level will allow for the user to click a location and generate a time series. Changing the area over which the spatial averaging is performed will modify the resolution of variable estimation.

Time series a: 16-day estimates of VCI for the selected region or commune selected for the last 18 months.