Satellite Images API for Agriculture: NDVI, EVI, True and False colour
Posted on 16 May 2018
By: Bronislava Stavnitskaya,
Product Manager, OpenWeather.
In this article, we would like to look in more detail at one of the essential elements of our Agro API: the Satellite Images API. The Satellite Images API is the dataset from the Landsat 8 and Sentinel-2 satellites on the basis of which we calculate quantitative indices, such as NDVI, EVI and others, and from which we also obtain ready-made images of territories in True and False colour, NDVI and EVI.
True colour and False colour
True colour – “True colour” is a rendering of the red, green and blue satellite imagery spectral bands to create the natural-looking RGB composite image.
False colour (b5 b4 b3) – “False colour” is a rendering using NIR (near infrared) band which is more useful for showing land cover and differentiating it from urban and farmland areas. In these images, it is possible to pick out different types of vegetation. Also easily discernible is the boundary between land and water, which enables changes in shorelines to be tracked.
NDVI and EVI vegetation indices
These are among the most common indices enabling quantitative assessment of vegetation cover. They are convenient for tracking the growth rate of plants and monitoring any changes in them.
NDVI – This is an index calculated according to a set formula which uses near infrared and red wavelengths. It is used in calculating and monitoring vegetation growth and its dynamics. The NDV Index is displayed in images using the white to green palette, where dark green indicates a good yield and white indicates a poor one or a lack of vegetation.
EVI – In areas of the dense canopy where the Leaf Area Index (LAI) is high, NDVI values can be improved using information from the blue wavelength. Information in this part of the spectrum can help correct atmospheric influences and background interference caused by soil.
We provide historical data, as well as satellite images that are as up to date as possible (allowing for the data source and cloud cover) for the very nearest time period. These images are available to all account users. Free tariff users can get all the satellite data that exists in our archive (the depth of this data is 1 year). For Small and Corporate tariff users, satellite data for all areas in the world is available. You can learn more about our pricing plans here.
Please note that there are limits to the total area that you can request data for, and to the number of requests you can make per minute. However, should you exceed these figures, we will continue to provide you with the data you need so that your work is not affected and your customers will not run and hide!*
You can find all the details and the full set of the Agro API’s capabilities here.
As always, we would be glad to hear your comments and suggestions regarding our product!
* At the end of your billing month, we will provide you with a separate bill for any additional area, beyond the tariff limits, for which you requested data.