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I am learning to preprocess Sentinel-2 data products using QGIS through various youtube videos. I downloaded and preprocessed everything accordingly using Semi-Automatic Classification pluggin. But the problem that I am facing is that I can only see 1 band under my product layers (Grey Band) as you can see. Whereas in the third image ( which is a screenshot from the tutorial) you can no band name is specified. I am confused why mine is specifically showing band 1 grey.

Here.

Even when I tried to represent the true color image from symbology, I choosed render type multicolor band but only band 1 grey is present there, I cant choose the red, green and blue bands shown in the videos and hence my image gets generated in black and whitehere also.

I am using the exact same products that was used in the videos so I am relatively sure that those bands are present there. This is my first time working with this.

What is it that I am doing wrong?

The last two images are from the videos where we can see the other band present. I have also tried preprocessing from other locations, same thing happens. enter image description here enter image description here

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Light can be decomposed in diferent band wavelengths. What you refer as a "true color image" would correspond to the wavelengths in the visible spectrum.

Sentinel-2 bands represent the amount of reflected light in a specific range of wavelength.

Check Sentinel-2 radiometric resolutions here.

So what you are seeing here is exactly what you should see. To generate a true color composition you need to take the bands from red, green and blue spectrum which in Sentinel-2 are bands 4 (red), 3 (green) and 2 (blue).

The last digits of the layer name identify the band. From your screenshots you have bands 8A (Narrow Near Infra Red), 11 and 12 (Short Wave infra Red).

There are many ways to generate a RGB composite but here is one of them:

  1. From QGIS menu go to Raster -> Miscellaneous -> Build Virtual Raster...
  2. Select bands 4, 3 and 2 as Input Layers

enter image description here

  1. Make sure you select Place each input file into a separate band option.

enter image description here

Notice the tool will generate a temporary file (virtual layer) but you can also specify a permanent output. Otherwise just left this as is and then export the result later if needed (right click -> export).

You will now have a multiband raster of 3 bands. It is possible that the default symbology due to the order of the inputs might have scrambled red, green and blue bands, just manually assign red, blue and green to the corresponding bands.

enter image description here

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