Apache SIS is a free software, Java language library for developing geospatial applications. SIS provides data structures for geographic data and associated metadata along with methods to manipulate those data structures. The SIS metadata module forms the base of the library and enables the creation of metadata objects which comply with the ISO 19115 metadata model and which can be read from or written to ISO 19139 compliant XML documents. The SIS referencing module will enable the construction of geodetic data structures for geospatial referencing based on the ISO 19111 model such as axis, projection and coordinate reference system definitions, along with the associated operations which enable the mathematical conversion of coordinates between different systems of reference. The SIS storage modules will provide a common approach to the reading and writing of grid coverages applicable to simple imagery as to many dimensional data structures.