DN. dl, Reflectance

[falahfakhri]

@AstraVic

Is it possible to create a pic like this (in % or in range from 0 to 1) ?

Yes, it is possible to create signature diagram using SNAP, for selected features, for instance vegetation, urban area, water, soil, et. al.

Please have a look at this video,

Exploring spectral response curves from Sentinel-2 in SNAP

@AstraVic

Why reflectances don’t have a unit?
Marco Peters wrote

Source

Have a look at this video as well explains the difference between the three component,

Digital Number, Radiance, and Reflectance

@AstraVic

So , when I create spectral view in Optical tools, I see dl or %? What kind of Sen2 product should I use? Because and L1C and L2A give similar result ,

Take a look at these threads,

TOA and BOA

sen2cor converts L1C products into L2A

Evaluation of Sentinel-2 Red-Edge Bands for Empirical Estimation of Green LAI and Chlorophyll Content

@AstraVic

What scientific books or papers do you recommend to read read? The main thing that it was written in simple language

remote sensing books pdf

INTRODUCTION TO REMOTE SENSING

The following is good book, if it is available in your library,

Remote Sensing and Image Interpretation, 7th Edition