Spectral Library: Get image spectra even with a map overlaid if the image is selected in Layers

[Agustin Lobo]

I get this behavior (see video recording), but I was expecting to collect the image spectra even if the map is overlaid (the image is selected in Layers).

Is this intentional or is it a bug?

[Andreas Janz]

The default behaviour is to use the top layer.

Here you can specify a specific layer:

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[Agustin Lobo]

That’s kind of hidden…

Then what is the Layer menu for?

For the user it would be very natural that the selected layer be the one feeding data to the spectra.

[Andreas Janz]

You mean that layer here, right?

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I see your point, and that would exactly match ENVI Classic behaviour. For the EnMAP-Box it is more complicated, because you can link multiple pixel profiles into the same spectral view. And also, the spectral view can visualize a whole spectral library.

Maybe you can discuss this topic in more detail with @Benjamin Jakimow , he wants to overhaul the Renderer Bands widget, see
https://github.com/EnMAP-Box/qgispluginsupport/issues/1

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[Agustin Lobo]

As a minor issue, the selection of the source layer is too hidden, I suggest bringing it up one step, just before Point.

[Andreas Janz]

Hi Agus,

I see the point, but in the general case, the user can define multiple profiles for a single row in the SpectralLibrary at the same time:

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So what you suggests would make sense for the (most common) case, where you only have a single source.

@Benjamin Jakimow any thoughts from your side? Do you want to provide a special handling for this case?

[Benjamin Jakimow]

@Agustin Lobo as mentioned above, the default is the “First raster layer”. If activates, the profile will be collected from the 1st raster layer from the layer stack (top-down search) with valid values (not no-data). The rational behind is that this is closest to what the mouse click intends to “touch”.

Indeed we could add an option “Selected/Current raster layer”. It would refer to the raster layer selected in the Layer Tree. In this case the layer could be invisible in the map, or even not exist in the layer tree of the map the mouse click is applied to.

[Agustin Lobo]

My concern is just with the fact that visualizing one image but selecting spectra from another one is very common, thus the selection of the source(s) data should be more straightforward for the user in the menu.

[Andreas Janz]

@Benjamin Jakimow may we allow the selection of the source here:

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This way, the user doesn’t need to expand the node → less clicks → happier users (?)

[Benjamin Jakimow]

+1 I like the idea of this shortcut

[Andreas Janz]

Alright, here is the follow-up issue: #1013

[Agustin Lobo]

Fine with me too.