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How can I extract a single band from multi-band raster in QGIS?

I have an remote sensed image which has 6 bands (including NDVI band), I want to display each band separately, but have no idea how to do. I have seen some questions similar here but none worked for me.

The original image (has 6 bands) is: enter image description here

I want to display the band 6 which should be like this: enter image description here

But I tried gdal_translate, and couldn't get the correct result.

What I have got is: enter image description here

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  • Thanks for answering but when I used gdal_translate, qgis showed that 'Error 4: Kayena.tif: No such file or directory". Would you know how to fix it?
    – Summer
    Mar 4 '19 at 7:12
  • Can you show your gdal command please?? And what OS you're using or can you give any usefull info?? Mar 4 '19 at 7:16
  • Use the full path to Kayena.tif and your output raster, it's saying it can't find the file in the one place it's looking for it so it mustn't be there; what your default path and full path is depends on your environment and OS but you can implicitly specify the full path to avoid confusing the tool. Mar 4 '19 at 7:58
  • Please take some time to clarify what you need. do you want the images side by side or on top of each others ? This would be completely different issue than your original question. If you can display one band, this is what you asked for. Then try to solve you second question (asking a new question if necessary).
    – radouxju
    Mar 4 '19 at 9:38
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This is a display issue: you want to display a continuous band using categories. You do not need to split your image to create a new new image: this can be done directly on the multiple band image, and you can add the multiple band layer multiple times on the map.

Go to layer properties > Symbology

Select singleband pseudocolor

Choose the band that you want to display

Select a color ramp

Select an interpolation method (discrete is OK)

Select a mode (I suggest quantile)

Select a number of classes

If you want to change some colors, double clic on the color. And if you want to change a threshol value, double clic on the threshold value.

enter image description here

As a remark, your band 6 doesn't look like the NDVI that you could derive from your image. It is more like some interpolated soil properties (or smoothed NDVI, but if you have a NIR band you could have a more precise one.)

EDIT: I now see from one of your comments that you don't use QGIS 3. In QGIS 2, this would be similar except that you must select "style" in the layer properties.

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  • Thanks for your answer. However, I tried this displaying approach before, it didn't show the image that it was supposed to. The expected result is that each band is displayed separately. As I added in question just now. I suspect that there is another way to do it.
    – Summer
    Mar 4 '19 at 8:48
  • you need to add the 6 band image 6 times as a layer, and then for each layer you select a different band to display.
    – radouxju
    Mar 4 '19 at 9:25
  • Thank you redouxju, it has been solved using your method. At first I couldn't get the correct result because of I didn't remove the nodata value.
    – Summer
    Mar 5 '19 at 0:52
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    @Summer if this answer solved your issue - gis.stackexchange.com/help/someone-answers
    – user2856
    Mar 5 '19 at 2:43
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You can use Rearrange bands tool from processing toolbox but select one band at a time and save the output as separate file:

enter image description here

Now the selected is only one band, and save the image as a new file:

enter image description here

The tool exists in Processing toolbox -> GDAL -> Raster Conversion -> Rearrange bands in QGIS 3.4.5 for the above tool.

Input 6 bands:

enter image description here

Output 1 band:

enter image description here

Repeat to select the bands you want or Run in Batch mode at the bottom of the tool.

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  • Thank you this looks good, unfortunately I couldnt update my QGIS as there is a plugin requiring the version below 2.3
    – Summer
    Mar 4 '19 at 7:49
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NDVI image with 6 bands?? It's not clear what you are asking. NDVI should be a single band raster, with values between -1.0 to 1.0. You might have a colored image with different values of NDVI, but it would then be 3 bands (RGB) not 6. And separating out one of the colors would not be useful in my opinion...

If you are trying to separate out the NDVI values above a certain threshold, then you could use the QGIS raster calculator with an expression like: ("ndvi" > 0.25) * "ndvi"

See here for the relevant QGIS documentation

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  • Sorry my mistake. It is not NDVI with 6 bands, but a remote sensed image that has 6 bands, including an NDVI band. I want to display the NDVI band, but somehow I couldn't. I just used the gdal_translate but the resulting image is not right.
    – Summer
    Mar 4 '19 at 7:41
  • I just put pics to the question. would you know how to get the NDVI band? Thanks!
    – Summer
    Mar 4 '19 at 7:54

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