Web application introduction
The web application you're about to explore is made to demonstrate how disparate RDF datasets containing geometry descriptions can be used.
Terminology from the
GOM,
FOG and
OMG ontologies is used to create the example RDF datasets.
The app currently only supports
OMG Level 2 linking patterns (click
from the side navigation bar to inspect the SPARQL queries implemented by this web application ), but could be expanded in the future to also support
OMG Level 1 and
OMG Level 3 patterns.
Note: the web application has been tested in Google Chrome and Mozilla Firefox. It might trigger errors in other browsers such as Apple Safari, Microsoft Internet Explorer or Microsoft Edge.
How to use this web application
Please follow these steps to query RDF datasources and visualize the retrieved geometry descriptions:
- Optional: click from the side navigation bar.
You can add new Linked Data sources and select the Linked Data sources you want to be considered by the web application.
By default, three demo RDF datasets, as documented here, are available for querying.
The Comunica query engine used in this app can query online RDF files (Turtle, TriG, N-quads, N-triples, Notation3, JSON-LD), SPARQL endpoints
and Triple Pattern Fragment (TPF) servers as long as no authentication is needed.
Of course, it is also possible to launch an RDF triplestore server with SPARQL endpoint or a TPF server on localhost.
If a geometry description, referenced from an RDF literal, is stored in a separate file, this file has to be retrievable via the web (e.g. hosted on Github or Dropbox (via shared link)).
- Optional: click from the side navigation bar to inspect the SPARQL queries implemented by this web application.
- Click from the side navigation bar to start retrieving geometry descriptions from the selected datasets.
- Select one of the available Coordinate Systems (CSs) from the dropdown list (top center) to "activate" it in the scene.
All geometry descriptions in the active CS or in a CS connected to the active CS (via a valid affine transformation) are subsequently rendered by the geometry engine.
- If necessary, press the following keys to help you during the navigation in the 3D viewer:
- "e": camera zoom extend and camera aligned to Z-up axis
- "u": camera aligned to Z-up axis
- "h": hide/show all geometry in the "active" CS except Nexus multiresolution meshes
- "+": increase point size for point cloud rendering
- "-": decrease point size for point cloud rendering
- Optional: click from the side navigation bar to find an overview of the loaded geometry descriptions and their properties. There are also buttons to zoom extend, hide/show (if viewable in active CS) and download the geometry. You can click each column header to sort the column content.
Note: The retrieved geometries from remote sources are rendered in the client browser.
Depending on the size of the geometry descriptions in the selected datasets, a considerable amount of data might be exchanged.
The loadable geometry in the three demo datasets has a total size of about 103.5 MB and are currently reloaded every time you press
(the query launch button).
The largest geometry descriptions however are included in the "contractor" dataset (~ 97 MB).
References
This web application is made and maintained by
Mathias Bonduel (KU Leuven) and is only meant for demoing the usage geometry in a Linked Data context. A large amount of optimization is still possible and errors might occur. The source code of the app resides in
this Github repository.
The web application can process geometry descriptions made using the following three complementary ontologies:
Several third party libraries were applied in this application: