There is a [demo ipython-notebook] (http://nbviewer.ipython.org/github/fkuhn/openlawsgii/blob/master/notebooks/giigraph_demo.ipynb) available.
The giigraph module is based on a prototype written during a code camp of the openslaws.eu project at the university of applied sciences Salzburg, Austria (March 20st and 21st 2015).
The open data project openlaws is aiming at providing legal knowledge freely and sophistically processed by using state of the art technologies. Since the project is based on an european level, it also tries to interlink as many european legal domains as possible.
The german legal domain has not yet been linked to openlaws and my task for the hackaton was to prototype the converter that takes the data provided on www.gesetze-im-internet.de and converts it to the geoff format of neo4j by using the specific attribute model for a database node.
Since time was short, I sticked to just converting the copyright-law file as a baseline.
GiiGraph is a class derived from MultiDiGraph of networkx so it can be easily enhanced lateron to meet requirements like backreference, crossreference, in-place reference, versioning etc.
First of all, I parsed the xml file with the well known lxml module (a binding to the libxml2 c-library). The important data items were read using the builtin xpath capabilities.
The graph was easily built after looking up the important german data items that have to be put in its place in the openlaws attribute model.
The root of all elements is the catalogue metadata of the law itself.
By using conditionals for the metafile structure, only articles were put into the graph. They all are chained via edges. Moreover, each article node is linked to the root element.
The package neonx is a converter to the json string of neo4j's geoff format. It was used to export the networkx graph to the geoff format.
As you can see, the class definition is quite small and readable by using already existing open source packages. Besides, the attribute model of openlaws is restricted to the very core of important information.
The gii website does not have an API to optain the data without any problems. A webcrawler must be written first to get all items in place. I will be using scrapy.
Copyright 2015 Florian Kuhn
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