Terms of use of Open Data are regulated by licenses, which allow the free use (also commercial), transfer, modification, linking and refinement of the data. However, a one-off small fee may be charged only for the provision of the data. Acceptable are such restrictions on use that oblige the authorship of the work to be identified or serve to preserve the "open" character of the data, even if it is passed on. This includes the naming of the authors and contributors (Attribution - BY), the transfer under the same or similar conditions (Share alike - SA) and the identification of changes in the transfer of data (Integrity). The Open Definition defines detailed conventions for this and lists existing standard licenses that are compliant (http://opendefinition.org/licenses/).
Characteristics of open data
Open data is data that can be used, changed and passed on by anyone and for any purpose.
This definition summarizes the understanding of open data and content as described in detail in the Open Definition published by the Open Knowledge Foundation. Although the Open Definition is not the only policy or interpretation of the term Open Data, it represents the general consensus of the Open Data Community and is cited accordingly.
Since any technical or legal restriction on the use of data reduces its potential value for society, the greatest possible freedom of movement is sought in this respect. Accordingly, the requirements of the Open Definition can be divided into technical and legal aspects:
The data should be available as a whole, preferably for free download. They should be machine-readable so that they can be processed by a computer and can be accessed and modified for each individual data element. Data should be in an open format that can beprocessed with at least one Free/Libre/Open Source program or tool.
