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The example images below show pixel reflections values of 10 Sentinel bands in the identify results window, graph option. Problem for me: When I switch from one pixel to the next, the scale will always change by taking the value of the band with the highest reflection as maximum, in the example from 4000 to 1100.

But for quick visual comparison purposes, I would like to fix the maximum for all pixels at 5000 (even if in some cases single bands would exceed this value and are not shown in the window). Unfortunately I couldn't find any option to do so.

Is there any built-in-option to to fix the y-scale of the identify-result-window at a given maximum? Or is there any analogue plugin or script? I'm using QGis 3.16 on Win 10.

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Referring to @Paulinas Answer from Jun 18 2021 at 6:59: enter image description here The example image shows the result window of the value tool. The Graph shows the spectral signals of 3 raster-layers, each layer 10 Bands: Points 1 to 10 belong to layer 1, points 11-20 to layer 2 ... .

Fixing the scale, my primary intention, works fine. On top it is also very nice, that you can observe more than just one layer at the same time (in comparison with the built-in identify tool).

BUT, with that type of graph it is hard for me to get a quick distinction between the layers or between the single bands, especially when the signals ar not very clear (as in the example). What I would miss is:

  • X-Scale-naming which refers to the layers/bands, e.g. by layer name and band number, or by distinct numbers, for example 1.1, 1.2, ... 1.10, 2.1., 2.2, ...2.10, ... ... (instead of consecutive numbering)

  • Points / connecting line: e.g. points in different colours for each layer (ideally with the option to give alternative colours to specific bands), or at least a break in the connection line when switching to the next layer

  • Result window with Auxiliary grid for easier reading of the values

Does anybody know another tool, which matches better to my needs? Or might there any option to adapt the value tool?: At least coloured points or breaks in the connection line according to the layers would help much.

By the way I don't wonna complain about the value tool at all. It is far more useful than the built-in variant for me. Great respect for the coder. I wasn't able to! But as I have to check many, many pixels, a tool with some of the above improvements would be nice...

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I did not find any way to fix the value range used for y axis in the graph view of the Identify value tool.

However, check out QGIS plugin called Value Tool (https://plugins.qgis.org/plugins/valuetool/). With that you can achieve what you wanted. By installing it you will get another panel in which you can observe the values of your raster layer (it will display the value of the pixel your mouse is pointed at) in the graph view, but with the option to control min and max values applied in the graph :)

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  • Thank you @paulina for that hint! The value tool helps a lot more than the built-in version. But for clarity reasons I would wish to have some extra features. In detail see edited section at my origin request. Anybody an idea about an alternative tool or adapting the value tool?
    – jaysigg
    Jun 28, 2021 at 7:50

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