gvSIG is a Geographic Information System (GIS), that is, a desktop application designed for capturing, storing, handling, analyzing and deploying any kind of referenced geographic information in order to solve management and planning complex problems. The gvSIG i18n is a web tool for collaborative localization of user interface strings, developed as a Plone application, designed for translation of Java properties and GNU gettext PO files. Depends on Plone product ModelDDvlPlone, hosted at OSOR at https://joinup.ec.europa.eu/page/osor.eu/projects/mddvlplone It is tested on Debian Ubuntu 8 and Windows (TM) XP and Vista. The tool has been developed under a contract by the company Model Driven Development sociedad limitada, in Valencia, Spain, and Antonio Carrasco Valero, for the local government ministry Conselleria de Infraestructuras y Transporte de la Generalidad Valenciana.