  We have now entered the new era of high-resolution imaging astronomy with the
beginning of the Event Horizon Telescope (EHT). The EHT can resolve the
dynamics of matter in the immediate vicinity around black holes at and below
the horizon scale. One of the candidate black holes, Sagittarius A* flares 1\-4
times a day depending on the wavelength. A possible interpretation of these
flares could be hotspots generated through magnetic reconnection events in the
accretion flow. In this paper, we construct a semi-analytical model for
hotspots that include the effects of shearing as a spot moves along the
accretion flow. We then explore the ability of the EHT to recover these
hotspots. Even including significant systematic uncertainties, such as thermal
noise, diffractive scattering, and background emission due to an accretion
disk, we were able to recover the hotspots and spacetime structure to
sub-percent precision. Moreover, by observing multiple flaring events we show
how the EHT could be used to tomographically map spacetime. This provides new
avenues for testing relativistic fluid dynamics and general relativity near the
event horizon of supermassive black holes.
