Coelho, AntónioBessa, MaximinoSousa, A. Augusto deFerreira, F. NunesPere Brunet and Nuno Correia and Gladimir Baranoski2014-01-312014-01-3120063-905673-60-6https://doi.org/10.2312/LocalChapterEvents/siacg/siacg06/109-119This paper presents Geospatial L-systems, a new extension of L-systems that incorporates geospatial awareness, and shows an application of this new tool in the expeditious modelling of urban environments, integrated with a modelling system with interoperable access to data sources. L-systems have been used in Computer Graphics for the modelling of plants, and in a few experiments to model urban environments. However, the lack of geospatial awareness is a limitation and in spite of some developments like open l-systems introduced the ability to communicate with the environment, there was a need for more flexibility. A new modelling system, named XL3D, generates virtual urban environments automatically from a XL3D document with a modelling specification. This modelling system accesses data sources in a interoperable way and the modelling processes are based on Lsystems. The integration of geospatial L-systems with the XL3D modelling system has increased its potential for automation and improved the potential to generate virtual urban environments with a higher level of detail and visual fidelity, with a lower level of complexity of the modelling processes. These facts are shown in a case study where a virtual urban environment taken from an area in the Porto downtown is generated by this solution.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling-Modeling packages; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism- Virtual Reality; F.4.2 [Mathematical Logic and Formal Languages]: Grammars and Other Rewriting Systems-Parallel rewriting systems (e.g., developmental systems, L-systems)