Raster histogram

1. Click the Add raster layer and select the file C:/OSGeo4W64/geodata/raster/s2/Subset_S2A_MSIL2A_20170619T.tif.
2. After clicking Open , the raster layer appears on the QGIS canvas.
3. Right click the layer name in the Layers panel and select Properties --> Histogramm

This dialog displays a histogram for all bands band. Left click and drag a box on the diagram to zoom in. Click on Pref/Actions and activate Draw as lines (Figure A).

Figure A: Line histograms of all bands

Click on Pref/Actions and deactivate Draw as lines. Activate Show selected band and Always show min/max markers.

The value range of the selected band data is evenly divided into bins. The histogram shows how many pixels of the image fall into each of the bins (Figure B)

Figure B: Histogram of a single selected band

. Click on . The graphics may be saved as png file.