[GRASS-user] Pansharpening Landsat 8 Imagery

[Veronica Andreo]

Hello Michele,

I haven't tried myself, but have you seen Markus's blog from some time
ago??

http://courses.neteler.org/processing-landsat-8-data-in-grass-gis-7-rgb-composites-and-pan-sharpening/

Maybe useful :)

Best,
Vero

2016-07-18 12:00 GMT-03:00 Michele Toma <michele.toma at airborne.aero>:

> Hi everyone,
>
>
>
> I was wondering if anyone had any suggestions or workarounds to the issue
> that I am having with pansharpening Landsat imagery? My email below has the
> steps that I took to attempt to pansharpen, but once I create a natural
> color image and run the pansharpen tool, I end up with distorted colors.
> Are there any other methods that I should try?
>
>
>
> Thanks in advance,
>
>
>
> Michele
>
>
>
> *From:* grass-user [mailto:grass-user-bounces at lists.osgeo.org] *On Behalf
> Of *Michele Toma
> *Sent:* Wednesday, July 13, 2016 5:39 PM
> *To:* grass-user at lists.osgeo.org
> *Subject:* [GRASS-user] Pansharpening Landsat 8 Imagery
>
>
>
> Hi everyone,
>
>
>
> I am having difficulty with pansharpening Landsat 8 imagery using this
> tutorial: http://planet.qgis.org/planet/tag/landsat/. I am able to create
> a natural color image, but the pansharpening results in images with
> distorted colors.
>
>
>
> Here are the steps that I have followed:
>
>
>
> 1.       Import all Landsat 8 bands to GRASS 7.0.4
>
> a.       r.in.gdal
> input=C:\Users\Michele\Desktop\LC81100362016082LGN00\LC81100362016082LGN00_B1.TIF
> output=LC81100362016082LGN00_B1 -k -e
>
> 2.       Converted digital number data to reflectance using i.landsat.toar
>
> a.       i.landsat.toar input=LC81100362016082LGN00_B
> output=LC81100362016082LGN00_refl
> metfile=C:\Users\Michele\Desktop\LC81100362016082LGN00\LC81100362016082LGN00_MTL.txt
> sensor=oli8 date=2016-03-22
>
> 3.       Color balanced using i.colors.enhance for bands 4, 3, 2 as RGB
> respectively
>
> a.       i.colors.enhance red=LC81100362016082LGN00_refl4 at Osaka
> green=LC81100362016082LGN00_refl3 at Osaka
> blue=LC81100362016082LGN00_refl2 at Osaka
>
> 4.       Displayed RGB map using bands 4, 3, 2 (I get a really great
> natural color image)
>
> 5.       Pansharpened bands 4, 3, 2 using band 8 as the panchromatic band
> with the IHS method
>
> a.       i.pansharpen red=LC81100362016082LGN00_refl4 at Osaka
> green=LC81100362016082LGN00_refl3 at Osaka
> blue=LC81100362016082LGN00_refl2 at Osaka
> pan=LC81100362016082LGN00_refl8 at Osaka output=LC81100362016082LGN00_ihs
> method=ihs
>
> 6.       Displayed RGB map with the “pansharpened” bands for 4, 3, 2
>
> 7.       Result: An image that is entirely gray (I found this link that
> says to use i.fusion.hpf, but following those instructions, I get “'make'
> is not recognized as an internal or external command, operable program or
> batch file.”
> http://gis.stackexchange.com/questions/111763/pan-sharpen-landsat-8-using-grass-7
> Am I supposed to use the GUI for this?)
>
>
>
> From searching online, I have found that the i.pansharpen module doesn’t
> take 16 bit imagery (which Landsat imagery is) but rather 8 bit. I found
> this link (
> http://gis.stackexchange.com/questions/39174/how-to-color-balance-false-composites-of-pan-sharpened-landsat-images-in-grass/67319#67319)
> that says to rescale the image. I attempted this twice:
>
>
>
> 1.       When I run it on the bands produced after running the
> i.landsat.toar module, I get numbers such as min=-0.00813278402972343 and
> max=1.58301384751301. After rescaling the images to 0-255 and proceeding
> with step 3 I end up with an entirely white image.
>
> 2.       However, if I rescale the original bands which all have ranges
> of 0-65535, to 0-255, then pansharpen, the result is a washed out version
> of the natural color image. I believe this has been pansharpened, but the
> colors are off. I also attempted to color balance the pansharpened bands
> but was unsuccessful as well.
>
>
>
> Am I rescaling the images incorrectly or is there another step I am
> getting wrong? Any guidance would be greatly appreciated.
>
>
>
> Thank you,
>
>
>
> Michele Toma
>
> michele.toma at airborne.aero
>
> www.airborne.aero
>
>
>
> [image: New Small2]
>
>
>
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