I am trying to clip trees out of a raster layer using polygon I've traced around them. I've created one polygon that I've copied for each tree so that each clipped raster contains the same width and height in pixels. But for some reason, some pixels from the edge become 0 values after the clip, and the pixel will have shifted. I'm guessing it is because my mask layer doesn't cover some pixels completely around the edges. There is no way to snap a polygon to edges of raster pixels that I know of. So how could I avoid this issue.