Before revision:  The basic idea is to learn an height-optimal triangulation based on the available reference data  and to use the learned triangulation  to compute piece-wise linear surface models for epochs in which only the observations of the monitoring stations are given.
After revision:  The basic idea is to learn an height-optimal triangulation based on the available reference data and to use the learned triangulation subsequently to compute piece-wise linear surface models for epochs in which only the observations of the monitoring stations are given.