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QGIS is a free, open source, cross platform (lin/win/mac) geographical information system (GIS)
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wavelength support for hyperspectral images #19127

Open qgib opened 10 years ago

qgib commented 10 years ago

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

Redmine category:rasters


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".


qgib commented 10 years ago

Author Name: Giovanni Manghi (@gioman)


qgib commented 10 years ago

Author Name: Etienne Tourigny (@etiennesky)


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 commented 10 years ago

Author Name: Bryan Karpowicz (Bryan Karpowicz)


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 commented 10 years ago

Author Name: Etienne Tourigny (@etiennesky)


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 commented 10 years ago

Author Name: Bryan Karpowicz (Bryan Karpowicz)


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.



qgib commented 10 years ago

Author Name: Matthias Kuhn (@m-kuhn)


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

qgib commented 10 years ago

Author Name: Etienne Tourigny (@etiennesky)


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 commented 10 years ago

Author Name: Bryan Karpowicz (Bryan Karpowicz)


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 commented 7 years ago

Author Name: Giovanni Manghi (@gioman)