I have developed algorithms to build and search a distributed k-d tree using Scala/Spark. Erik Erlandson of Red Hat has encouraged me to share the URL for the pre-print of my manuscript and source code: http://arxiv.org/abs/1512.06389 I will be revising this manuscript and refining the associated source code, so if anyone has suggestions for improvement, please feel free to communicate them to me. Thanks, Russ Brown