Satellite images and indexes NDVI and NDWI-Precision Agriculture

With the increase of the population and the increasingly growing demand for food by the same, agriculture has been forced to evolve and use technology related to satellite images .

It is necessary to satisfy the needs of a community hungry for nutrients, to ensure the good administration of agricultural resources and therefore the use of new technologies plays a fundamental role.

Well, agriculture has used Remote Sensing (RS) satellite or aerial technology for this purpose, putting space engineering at its service

What satellite images are taken?

The combination of satellite images allows us to analyze specific elements of the earth's surface based on their emission spectrum. Thanks to the different multispectral bands operation of the satellites we can interpret aspects such as vegetation, land uses or water masses.

The Sentinel-2 mission has the MSI (MultiSpectral Instrument) instrument that collects high spatial resolution data in order to monitor the Earth's surface.

The following satellite images show the difference in humidity in the different plots of the province of León.

We can compare with the following from the Murcia region.

Types of bands

  • The bands obtained from the Sentinel-2 satellite of ESA's Copernicus program are:
    • 1: 443 nm (azul), resolución 60 m/px
    • 2: 490 nm (azul), resolución 10 m/px
    • 3: 560 nm (verde), resolución 10 m/px
    • 4: 665 nm (rojo), resolución 10 m/px
    • 5: 705 nm (rojo), resolución 20 m/px
    • 6: 740 nm (ultrarojo), resolución 20 m/
    • 7: 783 nm (rojo lejano), resolución 20 m/px
    • 8: 842 nm (infrarrojo cercano), resolución 10 m/px
    • 9: 940 nm (vapor de agua), resolución 60 m/px
    • 10: 1375 nm (onda corta infarroja – Cirrus) , resolución 60 m/px
    • 11: 1610 nm (onda corta infrarrojo), resolución 20 m/px
    • 12: 2190 nm (onda corta infrarrojo 2), resolución 20 m/px
  • Specific RGB combinations will show us and discriminate the elements of our satellite images quickly.

How are satellite images analyzed?

With satellite images and using raster processing programs, we can calculate different indices such as:

With NDVI , the image is calculated pixel by pixel from the reflection of the wavelength of the near infrared and of the red and allows to generate an image that shows the relative biomass. The absorption of chlorophyll in the red band and the relatively high reflectance of the vegetation in the near infrared (NIR) band are also used to calculate this index.

For NDVI bands 8 and 4 are used with this relationship [(8-4) / (8 + 4)] while for NDWI Bands 3 and 8 are used with the relationship [(3-8) / (3 + 8)].

How does Plantae use this technology?

To correctly define the installation of the sensors and their location, in Plantae We use this technology defining to our clients where we would recommend to implement the probes.

In the lower satellite images it is expressed how we show the behavior of a farm with rainfall and irrigation, later marking the location.

Are you looking for specialized information?

Contact now for free and without obligation with our team of Agronomic Engineering

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