  We study the collimation and acceleration of the jets in the nearby giant
radio galaxy NGC 315, using multifrequency Very Long Baseline Array
observations and archival High Sensitivity Array and Very Large Array data. We
find that the jet geometry transitions from a semi-parabolic shape into a
conical/hyperbolic shape at a distance of $\approx10^5$ gravitational radii. We
constrain the frequency-dependent position of the core, from which we locate
the jet base. The jet collimation profile in the parabolic region is in good
agreement with the steady axisymmetric force-free electrodynamic solution for
the outermost poloidal magnetic field line anchored to the black hole event
horizon on the equatorial plane, similar to the nearby radio galaxies M87 and
NGC 6251. The velocity field derived from the asymmetry in brightness between
the jet and counterjet shows gradual acceleration up to the bulk Lorentz factor
of $\Gamma \sim 3$ in the region where the jet collimation occurs, confirming
the presence of the jet acceleration and collimation zone. These results
suggest that the jets are collimated by the pressure of the surrounding medium
and accelerated by converting Poynting flux to kinetic energy flux. We discover
limb-brightening of the jet in a limited distance range where the angular
resolution of our data is sufficient to resolve the jet transverse structure.
This indicates that either the jet has a stratified velocity field of
fast-inner and slow-outer layers or the particle acceleration process is more
efficient in the outer layer due to the interaction with the surroundings on
pc-scales.
