  Absolute cross sections for the {\it K}-shell photoionization of Be-like and
Li-like atomic nitrogen ions were measured by employing the ion-photon
merged-beam technique at the SOLEIL synchrotron radiation facility in
Saint-Aubin, France. High-resolution spectroscopy at nominal resolutions of 38
meV, 56 meV, 111 meV, 133 meV FWHM for Be-like and 125 meV FWHM for Li-like
atomic nitrogen ions was achieved for the photon energies ranging from 410 eV
up to 460 eV. The experimental measurements are compared with theoretical
estimates from the multi-configuration Dirac-Fock (MCDF), R-matrix and an
empirical method. The interplay between experiment and theory enabled the
identification and characterisation of the strong 1s $\rightarrow$ 2p
resonances features observed in the {\it K}-shell spectra of each ion and the
region around 460 eV for the 1s $\rightarrow$ 3p resonance of the N$^{3+}$ ion
yielding suitable agreement with experiment.
