Geodata is becoming an increasingly more central resource in research and teaching. The question as to how university members can reach the data they need easily is becoming ever more prominent: different data formats, data structure or even legal aspects hamper the availability of this information.
Development of geodata4edu.ch: metadata catalogue and services
The recently launched platform geodata4edu.ch offers Swiss universities central access to an extensive range of geodata from federal offices and cantons. Apart from a central search entry (metadata catalogue), which contains all the data available via geodata4edu.ch, two kinds of access (services) were set up to enable as broad a user group as possible to be covered. Consequently, the data can either be visualised directly in the browser and downloaded in excerpts (download service) or incorporated into a GIS programme (ArcGIS, QGIS in the pipeline; web services).
List of hits from the metadata catalogue geodata4edu.ch
The range of data is updated continuously and currently comprises swisstopo datasets such as landscape models, topographical and geological maps, the aerial photograph dataset SWISSIMAGE and the elevation model swissALTI3D. Datasets from various offices of the Canton of Aargau are also available; data from other cantons and federal offices will follow shortly. This enables members of Swiss universities to use the potential that geodata offers as broadly as possible – and outside the traditionally “spatial” subjects such as remote sensing, geography or spatial planning, too: issues from the social, political and information sciences are based increasingly frequently on spatial information and can be combined with other (factual) data to find answers.
Depending on the field of application and the users’ state of knowledge, one geodata4edu.ch service or another is then better suited to obtain the data. What the two approaches have in common, however: authentication through university access via SWITCHaai.
Layers from the swissTLM3D dataset visualised in the browser (download service)
Technical implementation and access to the services
In order to meet the aforementioned user requirements, the technical implementation of the access to both services was separated:
The download service (formerly GeoVITe) is based on a three-layer architecture with a clear separation of data (managed by a data storage level in the backend), application logic (consisting of server-sided geoservices) and a presentation layer (realised by a client-sided user interface in the frontend). Moreover, the download service is operated on the infrastructure of ETH Zurich’s IT Services and makes extensive use of open source software (e.g. QGIS Server, GDAL/OGR and GeoTools for the application logic). The complete user interface is structured on Java server technologies to guarantee authentication and communication with the server-sided application logic. In the process, the geoservices access the data in the backend, process it for user actions on the browser for presentation or download and ultimately provide the user interface with the corresponding response.
The technical infrastructure of the web services is built on SWITCHengines. The data is saved on an ArcSDE/MS SQL database in the backend and a FileStorage server and published as map, feature and image services via an Esri ArcGIS server REST API interface.
Layer of the swissTLM3D dataset in ArcGIS (web services)
These web services hosted on the ArcGIS server are organised for further usage via a federated Esri Portal for ArcGIS. To integrate the web services in the desktop client, the user connects after registering successfully on the ArcGIS server via “Portal for ArcGIS” and loads the web services into the corresponding desktop application software.
Connect with “Portal for ArcGIS” to use the geodata4edu.ch web services
This creates central, user-oriented access for any approach under the service geodata4edu.ch, which makes the use of geodata in all subjects at Swiss universities considerably more straightforward.