Spectral indices

[Agustin Lobo]

I think the following would be useful:

1. A menu for computing predefined spectral indices (including those defined by the user in a config file): tick on those of interest that would be saved, by default, as a multi-”band” .vrt file.
2. On-the fly computing of spectral indices for being displayed in a similar way as in the color space explorer. Note that indices are most often displayed in grey or pseudocolor scale, but in geology is not rare to display color composites of spectral indices.

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[Andreas Janz]

A menu for computing predefined spectral indices 

You mean in the main menu or somewhere else?

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[Andreas Janz]

On-the fly computing of spectral indices for being displayed in a similar way as in the color space explorer. Note that indices are most often displayed in grey or pseudocolor scale, but in geology is not rare to display color composites of spectral indices.

We have the Spectral Index Creator app, where you can do that. Have you tested it already in the dev version?

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[Agustin Lobo]

My bad, I was not clear enough.

I was thinking on a section named Predefined Spectral Indices (after Predefined Multiband Colors) within Custom Raster Rendering/Color Space Explorer, or perhaps a new Custom Raster Rendering/Spectral Indices Explorer panel.

What you suggest also makes sense, but would be rather for computing the indices. I was thinking on visualizing the indices (even as composites) before actually computing (some of) them. It would make sense as an exploration tool.

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[Andreas Janz]

Alright, understood.

What about just using the new Raster Layer Styling panel to render Spectral Indices directly?

Instead of only selecting original bands, we could allow the selection of Spectral Index Bands:

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I’ve already done something similar in another tool, where you can visualize normal bands and index bands:

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[Agustin Lobo]

Yes, that would be it.

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[Andreas Janz]

Maybe we don’t need to touch the  Raster Layer Styling panel to make that happen.

The Spectral Index Creator app can create a VRT raster with all the Spectral Indices you are interested in. This takes only a second.

Now select this VRT in the Raster Layer Styling panel, and you are good to go to visualize any index in RGB/Gray/Pseuso colors.

[Agustin Lobo]

I would rather have the possibility of visualizing the indices in the Raster Layer Styling panel directly and then save those needed only. But this is not a big issue. What you say would have the advantage of letting you concentrate on more important issues (such as #882)

[Andreas Janz]

What you say would have the advantage of letting you concentrate on more important issues (such as #882)

Yes

[Andreas Janz]

resolves #968 and #993

→ <<cset 7e9f3eed8f5c>>