banddata managementqgisqgis-3raster
In QGIS 3.16.8 I have a raster image in TIFF format which has 17 bands. I need to extract different band combinations as separate image files. Some of the combinations consist of images with single band only.
Is there a way in QGIS, where we can export a single band or combination of multiple bands as a image.
The gdal command cell input where I tried to translate raster layer and get the output is not working for me. I have attached the image for your reference.
It is not clear on weather you want to subset bands upon reading into R or extract a single band from an existing raster stack. Once illustrated, both are quite simple.
We can use the 3 band R logo as an example.
library(raster)
fn <- system.file("external/rlogo.grd", package="raster")
To subset a band from an R raster stack/brick you use a double bracket, like you are indexing a list object.
( r <- stack(fn) )
( r1 <- r[[1]] )
To read a single band from a multiband raster, on disk, you use the "raster" function with the "band" argument.
( r <- raster(fn, band = 1) )
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.
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.
Best Answer
Here is a trick to solve your problem.
From the top menu, go to Raster>Conversion>Translate.
Then, in the Translate window, perform the following tasks:
For example (To extract the first band):
For example (To extract the first two bands):
In this way, you can extract different bands and their combinations from an input image.
For more description, visit the documentation.