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I am using Python osgeo/gdal library to access Landsat 7 data (from different bands) as a numpy array. When looking at the data, I often see a very prominent comb-like banding effect. The image below shows a example and a bit of zoomed in detail as displayed by matplotlib. I see the same effect if I simply look at the image with an image viewer.

Is this normal, or am I reading the data wrong somehow? And if it is an artifact of the data, is there a standard way of "fixing" it?

Sample from image and zoomed in detail

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I think what you are seeing is the error which came about from the Landsat 7 Sensor when the Scan Line Corrector (SLC) failed in 2003.

Basically all imagery collected by Landsat 7 post 31 May 2003 has these artifacts in the images collected.

The Landsat website provides details on this: Landsat 7 Site

Following some of the links there are ways to correct this. There is also a "Gap masks" which allow for the identification of those areas where data is missing.

The link above describes the methodologies used to determine if a scene is salvageable. If it is, you can combine scenes to fill the gaps where data is missing.

https://landsat.usgs.gov/gap-phase-statistic-calculator

Will assist in identifying which scenes are best to use.

As an aside, if you look on the right hand side of this question you will see a number of similar questions relating to the Landsat 7 SLC failure. These links will also give you insights into how best to handle the error.

  • Thanks! A lot of figuring out the landsat stuff is knowing what all the acronyms actually mean! – Denise Draper May 14 '18 at 20:26

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