With imagery of sufficient resolution to clearly identify buildings, trees, and other structures, it is possible to remotely assess the suitability of a project site for solar. (blog.aurorasolar.com)
These structures are becoming so small that the usual magnetic measurement methods fail to provide data with sufficient resolution. (sciencedaily.com)
They're clever, but it's questionable whether they provide sufficient resolution down to the individual finger - level; they're also much larger than any consumer would probably want to wear. (slashgear.com)