Edit/View XMP Google Photosphere

I am looking for a way to view and edit the xmp data or tags that are embedded into photosphere images, for Google. In order to build photospheres, the xmp data must be added in. I tried using Digikam, but the version int he repos, 4.14, doesn't seem to read the xmp data and I'm not sure if exiv2 is reading it correctly, or, how to read it, for that matter. Does anyone know of a program that will easily add or edit the xmp data?