wavelength units should be handled as a bandwise information in GDAL Metadata widget

[Andreas Janz]

1. wavelength unit information is shown as a single item for the whole dataset. But it may be set for individual bands. See https://enmap-box.readthedocs.io/en/latest/general/glossary.html#term-wavelength-units for details.
   I would suggest to include the unit into the wavelength cell, e.g. instead of 0,46 show 0,46 Micrometers. Another solution would be to have an additional Wavelength units column in the table.

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2. The droplist indicates, that the user can actually change the wavelength units. But it seams that changing the current combobox item does nothing. The droplist should be removed.

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[Andreas Janz]

Not that the GDAL ENVI driver also puts wavelength information to the individual bands:

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This is a good idea in so for, that you can now do band subsetting without handling the list of wavelength at dataset level, but simply copy band metadata.

[Benjamin Jakimow]

Why should wavelength units differ between bands?

[Andreas Janz]

Why should wavelength units differ between bands?

As shown above, the GDAL ENVI driver also stores the wavelength and wavelength_units items individually at band level. This is a good idea, because now you can easily create a band subset using gdal.Translate.

Maybe even more important for answering your question: if wavelength and wavelength_units information is stored at band level, you can create band stacks from different rasters.
E.g., for stacking a band with Nanometers and a band with Micrometers together, you just have to copy the individual band metadata (i.e. gdal.Band.Set/GetMetadata_Dict), instead of translating everything to Nanometers or Micrometers, which would alter the original metadata.

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[Andreas Janz]

Benjamin, having an editable wavelength units combobox, that isn’t working properly, is a bug. After that is fixed, we can set this issue back to proposal.

[Andreas Janz]

Removing version: 3.10 (automated comment)

[Benjamin Jakimow]

qps update. resolves #786 - GDAL metadata (aaargh. pulled false branch in previous commit.)

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