The Map Is Not The Territory

A blog by Christian Willmes.

New SemanticMediawiki based OSGeo Member Map

| categories: webdev, semantic web, geospatial, osgeo, semantic mediawiki | View Comments

In this post, I give some background on the new Semantic Mediawik based OSGeo Members map, that replaced the userMap. Starting with the Mediawiki update and introducing Semantic Mediawiki, some words about the history of the userMap and most important an overview of the new implementation and possible additional applications of Semantic Mediawiki in the OSGeo Wiki are given.

The introduction of Semantic Mediawiki into the OSGeo Wiki

Recently, thanks to an effort by OSGeo SAC (namely by Martin Spott), the OSGeo Wiki underlying Mediawiki software was upgraded from an ancient version (I think it was 1.12) to the current 1.25.3. Additionally the Semantic Mediawiki (SMW) extension, including Semantic Maps was installed, to enhance the OSGeo Wiki with its features.

SMW is a Mediawiki extension, that allows to structure wiki content (as data) and provides tools for queriying, export and visualization of this structured data. The Semantic Maps extension adds the capabilitiy to visualize SMW content, containing data of the special type "Geographic Coordinate" on maps. SMW even offers an API that allows to query the structured data stored in the wiki from external applications and export data based on queries. SMW is a mature project running on many large Mediawiki implementations, by well known organizations like NASA, OLPC, The Free Software Directory, semanticweb.org, to name just a few.

The OSGeo Wiki userMap

The original OSGeo Wiki userMap, implemented by me in 2008 during an internship at WhereGroup, is now broken because of dependencies of the not anymore supported Mediawiki extension called Simple Forms. The extension implemented a parser hook, that allowed to store the spatial locations of users in a PostGIS database. And parser hooks for including OpenLayers based map into wiki pages, displaying a users Location as well as a map of all were implemented in this first version of the userMap. The now deprecated documentaion is for now still available in the wiki, to get an overview.

SMW based OSGeo Members map

The SMW data model was developed using a tool called mobo. Due to using mobo, it is possible to develop and maintain an SMW data model from a central point in a consistent manner, enhancing maintainability, coordinating possible collaboration and also allowing to grow the Schema to additional applications and scopes over time. Mobo is a command line toolset that helps building Semantic MediaWiki structure in an agile, model driven engineering (MDE) way. The Schema is formulated applying the JSON-Schema specification, in JSON or YAML notation, in a defined folder structure considering file naming conventions. A bit similar to some MVC frameworks for building a web applications domain. The documaentation including a tutorial and examples of the mobo toolkit, can be found here.

The development code files of the mobo model are stored and published in a GitHub repository, for community review and allowing anyone to send pull requests for helping to improve the SMW based capabilities of the OSGeo Wiki.

It was even possible, to save the locations entered through the previous userMap implementation into the mentioned PostGIS table. This was possible by exporting the data from the PosGIS table as CSV, applying some Python foo on the CSV (especially on the geometry wkb notation using Shapely) and importing the data into the wiki as CSV, using the Mediawiki DataTransfer Extension.

Conclusion and Outlook

The application of SMW technology in the OSGeo wiki has, with the introduction of the OSGeo Members model, created a valuable directory that gives a nice overview of the OSGeo community. It is possible to extend the model in the future, to a directory of Charter Members, or OSGeo Advocates. This would yield sortable tables and of course maps of these contacts.

It is even possible to develop models for the Service Providers, to replace the sometimes hard to maintain current Service Provider directory, or for example a model of the Geo4All laboratories to generate directory and an according map. But one of my favorite possible models would be a model for an Open Geo Data directory in the OSGeo wiki.

All these models and the emerging directories would be collaboratively created and maintained by the OSGeo community by just editing the wiki. And not yet to speak of what is possible with the Mediawiki API for querying the structured data and getting the results nicely in JSON format, and by far not yet to speak of enabling the SPARQL-Endpoint which comes with Semantic Mediawiki.

So, the OSGeo Wiki has a bright future If we want. I will do my best for this goal.

Have fun!


 

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