  Asteroseismology has become widely accepted as a benchmark for accurate and
precise fundamental stellar properties. It can therefore be used to validate
and calibrate stellar parameters derived from other approaches. Meanwhile, one
can leverage large-volume surveys in photometry, spectroscopy, and astrometry
to infer stellar parameters over a wide range of evolutionary stages,
independently of asteroseismology. Our pipeline, SEDEX, compares the spectral
energy distribution predicted by the MARCS and BOSZ model spectra with 32
photometric bandpasses, combining data from 9 major, large-volume photometric
surveys. We restrict the analysis to targets with available spectroscopy from
the APOGEE, GALAH, and RAVE surveys to lift the temperature-extinction
degeneracy. The cross-survey atmospheric parameter and uncertainty estimates
are homogenized with artificial neural networks. Validation of our results with
CHARA interferometry, HST CALSPEC spectrophotometry, and asteroseismology,
shows that we achieve high precision and accuracy. We present a catalog of
improved interstellar extinction ($\sigma_{A_V} \simeq$ 0.14 mag) and stellar
radii ($\sigma_R/R \simeq$ 7.4\%) for $\sim$1.5 million stars in the low- to
high-extinction ($A_V \lesssim 6 $ mag) fields observed by the spectroscopic
surveys. We derive global extinctions for 184 Gaia DR2 open clusters, and
confirm the differential extinction in NGC 6791 and NGC 6819 that have been
subject to extensive asteroseismic analysis. Furthermore, we report 36,854
double-lined spectroscopic main-sequence binary candidates. This catalog will
be valuable for providing constraints on detailed modelling of stars and for
constructing 3D dust maps of the Kepler field, the TESS CVZs, and the PLATO
long duration observation fields.
