The continued advances in mobile devices, geo-location wireless sensors and positioning technologies have led to a profusion of Moving Object (MO) data. However, conventional On-Line Analytical Processing (OLAP) systems cannot be applied to MO analysis because the position dimension evolves continuously over time. In this paper, we consider the representation of network-constrained MOs in OLAP systems and make the three following contributions: (i) We introduce a logical model to support continuous dimensions and facts. (ii) We propose an efficient data structure to index moving objects. (iii) Based on this index structure, we describe an algorithm which optimizes OLAP queries for analyzing MOs.