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I have two Landsat 8 satellite images from two different dates in may. When I import them in ArcGIS they slightly overlap but the pixel colours don't match making it hard to run an NDVI. I have been trying to run colour matching on the two datasets by creating a mosaic or raster catalogue but it doesn't work.

  • Have a read of landsat.usgs.gov/using-usgs-landsat-8-product with particular interest in solar reflectance and top of atmosphere correction for both images. There should still be some slight variation between the scenes but that will (should) get you a bit closer to a match. – Michael Stimson Dec 20 '17 at 23:22
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    computing NDVI has nothing to do with the colours that are displayed on screen. Of course it is better to make atmospheric correction, but having different display colours is not a issue if the values are correct. – radouxju Dec 21 '17 at 7:15
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There are several factors that may be causing the effects you are seeing:

  1. You have not atmospherically corrected the Landsat images. Especially if the images were acquired at different time periods, you will notice differences in pixel values between the two.
  2. The images were acquired at different time periods leading to variation in variables such as sun angle and vegetation.
  3. Your software is not applying any color matching.

I suspect the issue relates to not correcting the images to bottom of atmosphere reflectance.

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