Mapping out the spectrum of excited hadrons from data is a cornerstone to the understanding of the strong interaction. With the advent of high-precision photo and electroproduction data from JLab and other facilities, and the future data from GlueX, there is finally the chance to come to more conclusive answers regarding the resonance content.
    One challenge on this path is to combine the data of different reactions in a global analysis while respecting unitarity, analyticity, gauge invariance and other theoretical requirements such as chiral constraints. I will present recent results of the analysis of photon and pion-induced reactions that allow for the reliable extraction of resonance poles and residues.
    Special emphasis will be placed on future challenges in the analysis of excited mesons and the interconnections to baryon analysis. Universal principles like coupled-channel unitarity even apply to the analysis of upcoming data of resonances decaying in the finite volume of lattice simulations.