Calculate LAI( Leaf Area Index) from NDVI

s2tbx
#1

hi to everyone,

Is it possible to calculate LAI(Leaf Area Index) from NDVI with SNAP Toolbox? Thanks in advance.

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Leaf area index Sentinel2 L1C
#2

Hello Gaetano,

you don’t need to open three different topics for the same thing. Give the community the time to read it. :wink:

You should not expect to find a tool which calculates everything for you. Happily a tool to calculate the NDVI is already included. Then you could use a magic tool called “google” to search for LAI, NDVI and Sentinel-2. You could find plenty of information on how you could calculate the LAI approximatly (using SNAP’s Bandmath):



http://modis.gsfc.nasa.gov/sci_team/pubs/abstract.php?id=03075

ftp://ipl.uv.es/macenma/RAQRS/Art-IEEE-29mio.pdf
and many more…

Cheers,
Andreas

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#3

Hi @gaetano

Hopefully for you, a LAI processor has just been developed for SNAP, for Sentinel-2 data, and will be available in the upcoming 4.0 release. It is named “Biophysical Processor”, and computes several biophysicl variables : LAI, Cab, Cw, fAPAR and fCOVER.

The algorithm is more precise than what you can derive from NDVI, and actually consists in a neural network which inverts PROSAIL simulations.

Cheers,
Julien

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#4

Hi @jmalik
Can you please send me the link to the the documents where the Biophysical Processor equations are described in details ?

Thanks a lot ,
D

#5

We will publish on SNAP website sometimes next week. I’ll keep you posted

#6

Thanks a lot @jmalik

#7

Hi @jmalik
Any updates regarding Biophysical Processor equations used for SNAP tool2 ?

Thanks a lot,
D

#8

Dear @Daniel1,

as already reported in these posts


you can find the ATBD of the Biophysical processor here:

Federico

Biophysical parameter
#9

@FedericoF @jmalik
Hi.
I have one question.

I am using Biophysical Processor to Calculate LAI. When I get final image (.tiff) I get with two bands. One band is value of LAI, and what is the other band value? It has only 0 and 1 (I noticed that). Is there any relation with cloud mask or something? And which value is what? Thanks.

#10

Hi @Milutinke,

do you refer to the ‘lai_flags’ band?
Flags band can be visualized in SNAP using the ‘mask manager’ utility, and describes qualitatively the pixels which where not properly generated from the Biophysical processor (e.g. ‘lai_output_too_low’, ‘lai_output_too_high’).

Flags are stored as combination of binary ‘bit’ masks, and SNAP has readers for specific products in order to properly decode the quality flags. Their visualization can be more difficult if you use other software.

Hope this may help,

Federico

#11

More information can be found in this post:

#12

Hi guys,

have one of you ever tried the SNAP Biophysical Processor for tropical forest like mangroves ?
Is it suitable ?
Thanks in advance

#13

I have read many papers regarding LAI calculation. They have used the handheld canopy analyser for the LAI calculation and then make the relationship with different indices to the estimation of the LAI. They are not calculating the LAI from the imagery directly. So steps, papers and algorithms for calculation of LAI is available then please forward me. Thanks