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INDICE DEL TUTORIAL:
1.
Definición
3. Interacción
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NATURAL RESOURCES: NDVI ( Normalized Differential Vegetation Index ) |
OTROS ITEMS DE INTERES Imágenes satelitales y seguros ¿Qué es la percepción remota?
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29 of April of 1999 - Image NOAA 14 - Calculated NDVI 1,100km of resolution per pixel Zone: Uruguay The observation satellites usually transmit simultaneously their information in different spectral bands. Two of them, the corresponding to the region of red in the electromagnetic spectrum and the other in the near infrared (invisible region for the human eye) have a special interest from the point of view of the evaluation of the green cultures and its biomass. In the series NOAA for example, these bands correspond respectively to channels 1 and 2. The green and vigorous vegetation reflects much in band 1 less (red), region of absorption of the chlorophyll that in band 2, region of the high reflectance of the cellulose component. When the vegetation undergoes stress the values of band 1 increase and those of band 2 decrease. These properties took to define several vegetation indexes based on algebraic operations between the bands red and near infrared. One of the well know algorithms is the one of the Normalized Differential Vegetation Index (NDVI) that defines as NDVI = (band 2 - band 1)/(banda 2 + band 1). The values of NDVI are much greater for the vegetation than for the discovered ground, clouds and the water. The greater values correspond to the dense and healthful vegetation. These properties cause that the NDVI has been constituted in a most valuable tool for the evaluation of vegetable covers, as well as to study the classification and vegetal dynamics and its phenologic aspects.
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