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?