SDI 4 Apps - Uptake of open geographic information through innovative services based on linked data

HSlayers NG is a web mapping library written in Javascript. It extends OpenLayers 3 functionality and takes basic ideas from the previous HSlayers library, but uses modern JS frameworks instead of ExtJS 3 at the frontend and provides better adaptability. That’s why the NG (“Next Generation”) is added to its name. It is still under development and provided as open source. HSLayers is built in a modular way which enables the modules to be freely attached and removed as far as the dependencies for each of them are satisfied. The dependency checking is done automatically.
Core of framework is developed using AngularJS, requireJS and Bootstrap. This combination of frameworks was chosen mainly for providing fast and scalable development and for providing modern responsive layout of application.

Screenshot of HSL-NG

Screenshot of HSL-NG

Most important modules are:

  • Map: The map functionality is provided by OpenLayers3 and extended by some controls like navigation bar, scale line, attribution dialog, GPS and compass tracking etc. It supports multi-touch gestures, but the performance is highly dependent on the browser and mobile device hardware.
  • Layer manager and legend: Layer manager is used for listing all the map layers, displaying or hiding them and setting the transparency. The user can view layers metadata and attribution by clicking on it. A legend is fetched from the server and displayed in a separate panel for all the wms layers on the map. Grouping of layers in containers is also provided which enables a more user friendly and organized representation of layers for
  • OGC Web Services parser: This is used for GetCapabilities requests to different map servers and parsing the response. It can then be used for automatic or user initiated generation of map layers only by knowing the URL to the specific OGC standardized map service.
  • Print dialog: This is used for printing the map with the users browser print dialogue. The printing is done completely on client side by using HTML5 canvas graphics enabling a good performance.
  • Linked Open Data explorer: Eurostat explorer is a demo application (module) which queries Semantic Web data sources via SPARQL endpoints. It demonstrates the feasibility of automatic query building for Eurostat report data and displaying it on a map of NUTS2 regions (specified in GeoJSON file) according to the calculated transparency ratios. On the server side it uses a Virtuoso Universal Server which is a middleware and database engine hybrid that combines the functionality of a traditional RDBMS, ORDBMS, virtual database, RDF, XML, free-text, web application server and file server functionality in a single system.


Project management available at . Feel free and join our development team.

Source code is available at

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