Proland (for procedural landscape ) is the software platform developed for the NatSim project (see 8.2.2 ). The goal of this platform is the real-time rendering and editing of large landscapes. It currently integrates several results of the EVASION project-team on top of a terrain rendering algorithm: grass, individual animated trees, and volumetric forests (and the goal is to integrate future results, such as clouds or animated rivers). The terrain data can come from digital sources (elevation data, satellite photographs) and from vector data (spline curves representing linear features such as roads and rivers and areal features such as fields and forests). The vector data can be edited in real-time and can be used to constrain the vegetation (trees along roads or inside forests, but not in rivers).