Leaf's service uses Sentinel-2 data which has the highest resolution publicly available and revisits each field every 3 to 5 days.
We generate a total of 24 images for each intersected field: A GeoTiff for each band from Sentinel and processed RGB, NDVI and NDRE images.
The following table shows all the images with its resolutions and types: (TIFs are EPSG:4326, PNGs are EPSG:3857).
|NDVI.tif||10||tif raw NDVI values||EPSG:4326|
|NDVI_color.tif||10||tif colored NDVI||EPSG:4326|
|NDRE.tif||10||tif raw NDRE values||EPSG:4326|
|NDRE_color.tif||10||tif colored NDRE||EPSG:4326|
|B01.tif||60 meters||single band||EPSG:4326|
|NDVI_relative.png||NULL||png relative NDVI||EPSG:3857|
|NDVI_absolute.png||NULL||png absolute NDVI||EPSG:3857|
|NDRE_relative.png||NULL||png relative NDRE||EPSG:3857|
|NDRE_absolute.png||NULL||png absolute NDRE||EPSG:3857|
PNG files do not have resolution because they are scaled up by 800%.
We generate a colorized
NDRE_color.tif using a custom-built color ramp. See
the image below. If you prefer to use your own ramp, we recommend using
which is a pre calculated index file. You can import it into any GIS software,
like QGis, and use it as you please.
In addition, you will get the NDVI (i.e., we call them at Leaf as
NDVI.png) cut for your area of interest. The NDVI relative uses the minimum and maximum of the image of that date and, therefore, you would have a color scale to better visualize the differences of your harvest for that specific moment, whereas, the NDVI absolute and NDVI, whose range goes from
1, you can make comparisons on different dates, the difference between these files are the color ramp applied (i.e., in the NDVI all the values below
0 are bright red while in the NDVI absolute the color ramp begins at
-1 as the bright red and the value
1 as the bright green inteporlated in between). Same for NDRE.
Left - NDVI relative. Center - NDVI absolute. Right - NDVI.
We recommend using the Right one (just ndvi.png)
We use the cloud mask provided by Sentinel-2 to calculate the clouds coverage percentage.
See the Satellite API Reference for more information.