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@Osaka green=LC81100362016082LGN00_refl3@Osaka blue=LC81100362016082LGN00_refl2@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@Osaka green=LC81100362016082LGN00_refl3@Osaka blue=LC81100362016082LGN00_refl2@Osaka pan=LC81100362016082LGN00_refl8@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 [email protected]<mailto:[email protected]> www.airborne.aero [New Small2]
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