wavelength support for hyperspectral images

[qgib]

Author Name: Bryan Karpowicz (Bryan Karpowicz)
Original Redmine Issue: 10743

Redmine category:rasters

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When loading a hyperspectral image currently qgis will load the first three bands. It would be extremely useful if it could load some default color schemes like "true color", or "color infrared".

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• subset.hdr (Bryan Karpowicz)
• subset.img (Bryan Karpowicz)

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• fixed_version_id was configured as Future Release - Nice to have
• category_id was configured as Rasters

[qgib]

Author Name: Etienne Tourigny (@etiennesky)

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This would be nice indeed.

It would be better if you give more details about how it should work

1- how to define which bands are "true color" or "color infrared"
2- what to do exactly once these are identified. True color means assign the RGB colors to the right bands right? Now what about color infrared?

[qgib]

Author Name: Bryan Karpowicz (Bryan Karpowicz)

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I was thinking something similar to what ENVI does where RGB true color maps to R-0.64 µm, G-0.55 µm, and B-0.47 µm, and CIR maps to R-0.86 µm, G-0.65 µm, and B-0.55 µm. If those precise bands aren't available, pick the nearest neighbor.

Use those to start, and maybe add something else in the 0.4-2.5 µm as this is typically what most new hyperspectral imagers shoot for.

[qgib]

Author Name: Etienne Tourigny (@etiennesky)

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That would require some guessing or metadata to know the wavelength of each band... if you can give some specific information it would be useful.

[qgib]

Author Name: Bryan Karpowicz (Bryan Karpowicz)

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I was thinking that if you had metadata like exists in a ENVI raster, you could pull that information, interpolate which bands to use, if exists, otherwise just use bands as it exists now.

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• 7551 was configured as subset.hdr
• 7552 was configured as subset.img

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• subset.hdr (Bryan Karpowicz)
• subset.img (Bryan Karpowicz)

[qgib]

Author Name: Matthias Kuhn (@m-kuhn)

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Keeping the information about the wavelength in the band metadata would also be useful for other things like spectral plots.

[qgib]

Author Name: Etienne Tourigny (@etiennesky)

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Bryan - is this only for ENVI datasets? DO you have an exmaple of e.g. GTiff datasets that have wavelength information?

It would be interesting to use this for MODIS and Landsat imagery, although how would we guess the proper bands or even reliably recognize the source as MODIS or Landsat?

[qgib]

Author Name: Bryan Karpowicz (Bryan Karpowicz)

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Off the top of my head, I can't think of any data source which has a geotiff with wavelength information embedded in it. Landsat just refers to their's by band #, and I think MODIS does also. I'm pretty sure you could identify MODIS identifying metadata embedded within the hdf 4 file.

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• easy_fix was configured as 0