  The product of the previously constructed 3D maps of stellar reddening
(Gontcharov 2010) and $R_V$ variations (Gontcharov 2012) has allowed us to
produce a 3D interstellar extinction map within the nearest kiloparsec from the
Sun with a spatial resolution of 50 pc and an accuracy of $0.2^m$. This map is
compared with the 2D reddening map by Schlegel et al. (1998), the 3D extinction
map at high latitudes by Jones et al. (2011), and the analytical extinction
models by Arenou et al. (1992) and Gontcharov (2009). In all cases, we have
found good agreement and show that there are no systematic errors in the new
map everywhere except the direction toward the Galactic center. We have found
that the map by Schlegel et al. (1998) reaches saturation near the Galactic
equator at $E_{(B-V)}>0.8^m$, has a zero-point error and systematic errors
gradually increasing with reddening, and among the analytical models those that
take into account the extinction in the Gould Belt are more accurate. Our
extinction map shows that it is determined by reddening variations at low
latitudes and $R_V$ variations at high ones. This naturally explains the
contradictory data on the correlation or anticorrelation between reddening and
$R_V$ available in the literature. There is a correlation in a thin layer near
the Galactic equator, because both reddening and $R_V$ here increase toward the
Galactic center. There is an anticorrelation outside this layer, because higher
values of $R_V$ correspond to lower reddening at high and middle latitudes.
Systematic differences in sizes and other properties of the dust grains in
different parts of the Galaxy manifest themselves in this way. The largest
structures within the nearest kiloparsec, including the Local Bubble, the Gould
Belt, the Great Tunnel, the Scorpius, Perseus, Orion, and other complexes, have
manifested themselves in the constructed map.
