Hello Hugo Raúl Bocci , I do not know if I understood your question correctly, but if you just want to know (based on NDVI) which percentage of a specific area is covered by vegetation you can use ArcGIS or QGIS for instance. To do so you have to interpret NDVI values of your images first.

Short summary: NDVI values smaller than 0.1 correspond to areas without any vegetation, like rocks, sand, water bodies or snow. From 0.1 to 0.2 you have almost no vegetation. Spare vegetation like senescing crops, shrubs and also some types of grassland have moderate NDVI values from approximately 0.2 to 0.5. High NDVI values (higher than 0.6) indicate dense vegetation structures, like forests or crops at their peak growth rate.

To calculate vegetation cover percentages you have to select all pixels representing vegetation, calculate the resulting area and compare this area to your whole study site for example. But keep in mind, that vegetation cover and therefore NDVI values can change over time.

I hope this helps!

Best regards Paul

Once you have NDVI, you need to classify the results from your raster file using the saptial analisyt tools. As a result you will have total of pixels per ndvi value. Just add a new fied in the raster table and calculate the percentage of each class according to the total of pixel.

Generally, you cannot. The exception could be an open to closed grassland in a relatively small area.

For principles of NDVI as proxy for green grass biomass see for example our paper:

Ground-based reflectance measurements for standing crop estimates

For wood biomass

Carbon Stock of European Beech Forest; A Case at Mt. Pizzalto, Italy e.g.

For continental/national cover mapping principles see for example our paper:

Comparison of fine resolution census and image-based national forest

inventories: a case study of Rwanda.

For local cover mapping with ground data see for example

From monospecific to mixed forest after fire?

An early forecast for the montane belt of Majella, Italy

Answering three questions to yourself may help in your decision:

• tree canopy cover (forest), herbaceous cover (grassland) or mixed (e.g. savanna)?
• with/without cover data from ground survey?
• for what purpose you need cover information?

Please have a quick look on these posts :

https://www.researchgate.net/post/How_does_one_calculate_the_percent_vegetation_cover_using_NDVI_method

https://www.researchgate.net/post/How_can_I_calculate_vegetation_cover_from_ndvi

https://gisgeography.com/ndvi-normalized-difference-vegetation-index/

https://gisgeography.com/how-to-ndvi-maps-arcgis/

Hola Hugo,

Podrías encontrar una relación pero tendrías que validarlo primero, para que tipo de vegetación es y a qué escala estás trabajando?

A priori podría haber una correlación a menor cobertura menor NDVI pero sin calibrarlo es imposible tener certeza ya que el NDVI depende de muchos factores.

Si querés escribirme con algún detalle más del contexto de tu trabajo te podría dar alguna otra idea

saludos!

Try tool GISUS

Hello,

The vegetation cover percentage can be estimated from the tiff images of those NDVI, either in the ArcGIS using the raster calculator or directly in the GEE. But, firstly, you will need to decide the vegetation type too for which you need to calculate.

The very recent study on NDVI may also help you if you are using GEE:

Article The Grass Is Not Always Greener on the Other Side: Seasonal ...

Cheers

Hello Hugo Raúl Bocci,

Normalized Difference Vegetation Index (NDVI) describes the greenness by measuring the difference between near-infrared (which vegetation strongly reflects) and red light (which vegetation absorbs), which creates a single-band dataset that mainly represents vegetation density and vigor.

NDVI values range from +1.0 to -1.0. Areas of barren rock, sand, or snow usually show very low NDVI values (for example, 0.1 or less). Sparse vegetation such as shrubs and grasslands may result in moderate NDVI values (approximately 0.2 to 0.5). High NDVI values (approximately 0.6 to 0.9) correspond to dense vegetation such as that found in temperate and tropical forests or crops at their peak growth stage.

Extract the Area and Percentage in ArcGIS:

First, Convert the classified Raster to Polygon. Then, use Tabulate Intersection.

Second, Use Zonal Statistics (Spatial Analyst Toolbox).

Hi,

You use ARC GIS software

then use the raster table and calculate the percentage of each class according to the total of the pixel.

Dear Hugo Raúl Bocci ,

based on what I could understand from your question, my answer is that you can use ENVI and/or ArcGIS software. Take ENVI software for instance; after stacking spectral bands of NIR - Red and applying the NDVI transformation, you can click on the image for quick stats and regarding histogram. You can also export the schematic result into an excel sheet. There you can analyze your results; total number of the pixels creating the entire image, as well as the number of pixels classified between ranges -1 and 1.

NDVI values close to -1 mainly represent areas covered with water. Negative values closer to zero, represent areas covered with bare soil, rocks and/or urban areas. NDVI values greater than 0.6 - 0.7 often represent dense vegetation covers.

For vegetation cover analysis, pixels having NDVI values greater than 0.2 - 0.3 are most often included in the process.

There you go! Now you have the total number of pixels creating the image and the number of pixels having NDVI values grater than 0.2 or 0.3. This should do! Good luck :)

This index defines values ​​from -1.0 to 1.0, basically representing greens, where negative values ​​are mainly formed from clouds, water and snow, and values ​​close to zero are primarily formed from rocks and bare soil. Very small values ​​(0.1 or less) of the NDVI function correspond to empty areas of rocks, sand or snow. Moderate values ​​(from 0.2 to 0.3) represent shrubs and meadows, while large values ​​(from 0.6 to 0.8) indicate temperate and tropical forests. Crop Monitoring successfully utilizes this scale to show farmers which parts of their fields have dense, moderate, or sparse vegetation at any given moment.

https://eos.com/ndvi/#:~:text=According%20to%20this%20formula%2C%20the,the%20sum%20of%20these%20intensities.

Dear Hugo Raúl Bocci

You could mask the vegetation cover from the NDVI image using a threshold value, then save the resultant image (fraction image). The next step is to calculate the vegetation cover area using some softwares, such as ArcGIS. To get the vegetation cover percentage, you should get the entire area of your study region. Good luck.