I'm not sure how to ask my question in generic terms, but here's what I want to do.
I have a 360°x180° panorama photo. I took the photo with an app (Google PhotoSphere). Unfortunately my app doesn't save the individual photos I took, only the auto stitched panorama, with the "center" of the photo of its choosing.
I'd like to recenter, crop, reproject, etc. the photo, just as I would as if I had stitched individual photos into a panorama with a panostitching application like Hugin.
How can I bring a full panorama photo into Hugin (or similar software) so that I can manipulate the photo to my choosing?
My goal would be to export a new panorama photo (and not necessarily a 360x180).
Currently my only option is to view the photo in panorama viewing software, and take screenshots. However, this of course limits my resolution to my monitor, and only in the projection they're presenting it in.