The Research Institute in Urban Sciences and Techniques (IRSTV - http://www.irstv.fr) is a French research federation of the National Center for Scientific Research (CNRS - http://www.cnrs.fr). The IRSTV comprises over twenty urban research laboratories and approximately 200 multidisciplinary collaborators who work on projects dealing with sustainability issues on a city scale, such as the role of plants in sustainable urban development (VegDUD) or the environmental impacts of various urban mobility plans (Eval-PDU).The IRSTV’s multidisciplinary Geographic Information System (GIS) team, composed of geographers, computer scientists and mathematicians, actively researches and develops innovative GIS methods and tools. Its primary focus is the development and maintenance of the OrbisGIS (http://www.orbisgis.org) [1] platform, which is used by various research groups in order to analyze and model cities based on geographic data.Confronted with the need for a mature relational database management system, the team decided in 2013 to replace OrbisGIS’s original database system GDMS [2] by the H2 database (http://www.h2database.com). This choice brought greater modelling flexibility, improved performance and better interoperability with other databases. At that time, however, H2 had no Geometry data type. The team collaborated with the H2 team to add basic support for Geometries, but didn’t stop there. They created an open-source spatial extension of H2 called H2GIS (http://www.h2gis.org).H2GIS contains multiple spatial functions, including those specified by the OGC's Simple Features for SQL standards (http://www.opengeospatial.org/standards/sfs). In addition, it includes additional spatial functions the team has developed that extend and complement the SFSQL functions. Examples include ST_CompactnessRatio (for urban morphology) and ST_Tin (for hydrology).Both H2 and H2GIS are fully written in Java and can be used in embedded mode in order to spatially enable any Java application with a small memory footprint. Moreover, H2GIS is based on a robust and well-known open source library for geometry known as the JTS Topology Suite (http://sourceforge.net/projects/jts-topo-suite).