  We present a new algorithm to perform wide-field radio interferometric image
reconstruction, with exact non-coplanar correction, that scales to big-data.
This algorithm allows us to image 2 billion visibilities on 50 nodes of a
computing cluster for a 25 by 25 degree field of view, in a little over an
hour. We build on the recently developed distributed $w$-stacking
$w$-projection hybrid algorithm, extending it to include a new distributed
degridding algorithm that balances the computational load of the $w$-projection
gridding kernels. The implementation of our algorithm is made publicly
available in the PURIFY software package. Wide-field image reconstruction for
data sets of this size cannot be performed effectively using the allocated
computational resources without computational load balancing, demonstrating
that our algorithms are critical for next-generation wide-field radio
interferometers.
