3D maps of interstellar dust in the Local Arm: using $Gaia$, 2MASS and
  APOGEE-DR14
  Gaia data and stellar surveys open the way to the construction of detailed 3D
maps of the Galactic interstellar (IS) dust based on the synthesis of star
distances and extinctions. Reliable extinction measurements require very
accurate photometric calibrations. We show the first step of an iterative
process linking 3D dust maps and photometric calibrations and improving them
simultaneously. Our previous 3D map of nearby IS dust was used to select low
reddening SDSS/APOGEE-DR14 red giants, and this database served for an
empirical effective temperature- and metallicity-dependent photometric
calibration in the Gaia G and 2MASS Ks bands. This calibration has been
combined with Gaia G-band empirical extinction coefficients recently published,
G, J and Ks photometry and APOGEE atmospheric parameters to derive the
extinction of a large fraction of the survey targets. Distances were estimated
independently using isochrones and the magnitude-independent extinction
K(J-Ks). This new dataset has been merged with the one used for the earlier
version of dust map. A new Bayesian inversion of distance-extinction pairs has
been performed to produce an updated 3D map. We present several properties of
the new map. Its comparison with 2D dust emission reveals that all large dust
shells seen in emission at mid- and high-latitude are closer than 300pc. The
updated distribution constrains the well debated, X-ray bright North Polar Spur
to originate beyond 800 pc. We use the Orion region to illustrate additional
details and distant clouds. On the large scale the map reveals a complex
structure of the Local Arm. 2 to 3 kpc-long chains of clouds appear in planes
tilted by 15 deg with respect to the Galactic plane. A series of cavities
oriented along a l=60-240deg axis crosses the Arm. (http://stilism.obspm.fr)
