Integrating raster and vector spatial representations with interaction graphs for multi-scale environmental simulations

Session F5: Advances in Environmental Software Systems

Nowadays, developing tools for modelling complex system is a mandatory issue in environmental research. Environmental modelling implies taking into account processes at different scales of space and time. Ocelet is a domain specific environmental modelling language that uses graphs to describe how spatial entities in the system interact, with functions attached to the arcs of the graphs that are activated within scenarios to represent the dynamics of the system. The language has a strong focus on spatial interactions where the vector format is used for attributing geometries to entities, thus allowing a precise description of their shapes. However, the vector format is not appropriate for representing spatially continuous information for which the grid format is more efficient. In this paper, we describe how the grid format was formalized in Ocelet to allow a joint use with the vector format and interaction graphs, together with the key concepts and constraints for the combination of the two spatial formats. In this formalization, entities can be cells of different predefined shapes (square, beehive) and sizes. Processes can then be described with relations between cells that are handled as proper entities with their own properties as defined by the modeller. An example is given to illustrate this combination with a case study on water runoff modelling in a tropical insular environment subject to urban sprawl and soil sealing.