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I am analyzing forest cover change using 3 time-series Landsat data. The whole scene (185 x 185 km) images overlap in ArcMap display completely. However, when I subset/clip the images to my study site using a polygon, one of three images does not overlap with other two. It shows a bit displacement (nearly half pixel). Hence I can not go further with my analysis of forest change change.

To note, all layers/images have same datum/projection. I tried to image-to-image georegister the non-overlapping image with another image to nearly 0 rmse accuracy. However, when I clipped/extracted the study area portion again from this image with that polygon, the image again was not overlapping with the other two!

How can I get all these images spatially overlap completely?

What are the possible problems which might arise in finding forest cover and biomass change for 3 time-series years using those 3 images?

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Solution 1: Using the 'Snap Raster' option.ArcMap> Clip (Data management Tool)> Environments>Processing Extent> Snap Raster> Select the raster to which you want your non-matching raster to match with>Done!

Solution 2: Using the 'Shift' raster option to visually move the non-matching raster with mouse to the other rasters. Right click on top of ArcMap> Georeferencing>Select image you want to shift>Select Shift>Move cursor/hand by pressing and holding>Export the raster once perfactly matched with others. Done!

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