Belger, GernotHaase, MichaelLippert, KajMoeller, AndreasPage, BerndSchreiber, Martin2019-09-162019-09-162008https://dl.gi.de/handle/20.500.12116/26410In recent years a large number of open source solutions emerged which are of special interest to Environmental Informatics. Open source is now no longer just a playground of universities, research institutes and committed individuals who are communicating via the Internet to make ideas come to reality. Open source is also increasingly reflected in the business models of small and medium seized enterprises as well as well-known large IT companies. Different viewpoints on the issue of open source software from the Open Source Initiative and the Free Software Foundation are presented and analyzed. An introduction to open source license categories is given and compatibility issues of popular and widely used open source software licenses are discussed. The paper also introduces to basic strategies how to set up an open source project. A certain charm lies in the creation and establishment of one’s own open source project. This paper presents the story (Odyssey) of the open source project Kalypso (http://kalypso.sourceforge.net/). Kalypso encompasses a software palette for water resources modeling (e.g. hydrologic and hydraulic models) which was built on the basis of the powerful Kalypso framework. This framework allows to build extensive decision support and information systems including among others spatial data management and analysis, time series management and analysis, generation and management of reports, database access and accessing existing executable numerical models from the fields of environmental and water resources modeling. The paper introduces to the Kalypso project and presents the work spent to publish Kalypso on an open source platform.Text/Conference Paper