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I am new to JavaScript in GEE.

I am looking to do an atmospheric correction of Sentinel L1C images between 2016 and 2018, so I can complete my timeseries of BOA images of Sentinel. Using Atmospheric correction for Sentinel 2 level 1-c in the Google Earth Engine Java API) and @EliasBerra's code, I am able to apply a correct atmospheric correction to the first image in my Image Collection.

However, my goal is to achieve an atmospheric correction of my entire Image Collection.For this, I tried to use the map function instead of the first() function, but so far without success.

I would like to be able to make these atmospheric corrections only in GEE without having to download the images.

Here is my code for the moment :

// ---- Area of Interest (AOI) and User parameters
var geometry = ee.FeatureCollection('users/pierrelchn/Sites_Norm');
var start_date = '2016-01-01';
var end_date   = '2018-12-31';

var criteria = ee.Filter.and(
    ee.Filter.bounds(geometry), ee.Filter.date(start_date, end_date));
var cloud_perc = 20;//Max cloud percentile per scene.    

// -- Collections of Sentinel 2 TOA data
var S2_col = ee.ImageCollection("COPERNICUS/S2")
                .filter(criteria)
                .filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', cloud_perc));
                
                
// - Import the SIAC atmospheric correction module
var siac = require('users/marcyinfeng/utils:SIAC');

// - Apply SIAC and retrieve bottom of atmosphere (BOA) reflectance
var S2_boa = siac.get_sur(S2_col.first()); 


// - Check and visualization
var Color_comp_01 = {bands:"B4,B3,B2", min: 0.0, max: 0.2, gamma: 1};
var Color_comp =    {bands:"B4,B3,B2", min:200, max:2000, gamma: 1};
Map.addLayer(S2_col.first(), Color_comp, 'TOA');
Map.addLayer(S2_boa, Color_comp_01, 'BOA');
Map.centerObject(S2_col.first())

Or here https://code.earthengine.google.com/8a931e8e6e4c64a139cfaabd7161872f

1 Answer 1

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If you can apply it to one image, you can apply it to all images with map:

var S2_boa = S2_col.map(function(image){ 
    return siac.get_sur(image);
})
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