  A continuum crowd flow model is reformulated in the Lagrangian coordinate
system. The system has proven to give computational advantages over the
traditional Eulerian coordinate system for (one-dimensional) road traffic flow.
Our extension of the model and simulation method to (two-dimensional) crowd
flow paves the way to explore whether the advantages also hold in two
dimensions. This paper provides a first exploration and shows that a model and
simulation method for two-dimensional crowd flow can be developed in the
Lagrangian coordinate system and that is leads to promising results.
