SMS platform exposes a set of predefined SPARQL query templates as RESTful Web APIs in order to facilitate usage of the interlinked data by developers who are not familiar with the SPARQL query language. The Web services also allow better management of data access (in case authentication and authorization are needed) while monitoring the data usage for optimizing the queries and provide load balancing on the services infrastructure (e.g. due to reasons of data size and performance of the respective geospatial queries, scalability of Linked Geo Data platforms is a critical issue and needs to be dealt by distributing the services into a set of composable micro services). An important benefit of exposing data as service is the ability to build applications which combine one or more services with other existing services and applications to build novel and innovative STI applications. SMS uses Swagger to document the APIs of the exposed Linked Data services. The full documentation of services is available at .

The APIs are generally categorized into the following categories:

  1. Metadata Services and Applications
  2. Data Enrichment Services and Applications
    1. Named Entity Recognition
    2. Data Harmonization
    3. Geo-enrichment
  3. Data Linking Services and Applications

Metadata Services and Applications

Metadata helps potential users of a dataset to decide whether the dataset is appropriate for their purposes or not. RISIS project aims to provide a distributed infrastructure for research and innovation dynamics and policies. This infrastructure has a collection of various heterogeneous datasets that are not always publicly accessible due to privacy issues, and often require a researcher to be physically at the dataset location. To access these datasets, one needs to be granted an access request. This administrative detour that a researcher has to endure prior to detecting which dataset to use for a particular research question can reduce the number of RISIS datasets visitors. It has been shown that research publications that provide access to their base data yield consistently higher citation rates than those that do not. Therefore, to attract more users, to visit and cite RISIS datasets, SMS provides a dataset metadata service and application - modelled using the Resource Description Framework (RDF) - that allows researchers to search for data, and have an in-depth understanding of the data without the need to directly access it. Metadata service allows dataset holders to describe their datasets in a detailed, consistent and uniform way, store the description and if needed modify the stored metadata. The metadata can also be utilized to facilitate data integration as shown below:

In order to enable end-users to easily view and edit metadata, SMS provides a metadata editor application built on top of the metadata services. This application allows dataset owners to edit the metadata related to their datasets in different categories. Furthermore, for researchers interested in RISIS datasets, it provides interfaces on portal to view metadata and then request to get access to the data. The following video demonstrates how the metadata editor works:

Data Enrichment Services and Applications

SMS provides a set of services and applications that allow users to enrich their data by adding complementary data to their current data. There are three categories of data-enrichment services provided:

Named Entity Recognition

Named-entity recognition (NER) (also known as entity identification, entity chunking and entity extraction) is a subtask of information extraction that seeks to locate and classify named entities in text into predefined categories such as the names of persons, organizations, locations, expressions of times, quantities, monetary values, percentages, etc. Given a dataset which has one or more attributes with textual values, SMS NER service can extract named entities from the text and more importantly connect the extracted entities to a knowledge graph or taxonomy (which can then provide more data about those entities).

By default, SMS employs DBpedia Spotlight service for NER. However, any arbitrary NER service can be plugged into SMS NER service as long as the output of service is reconciled to SMS named entities annotation model. DBpedia Spotlight automatically annotates mentions of DBpedia (structured information extracted from Wikipedia) resources in text. The extracted entities map to a taxonomy of general knowledge (as shown in the following figure, DBpedia, Freebase and ontologies) which helps users to better browse and analyze a dataset taking a particular domain of interest.

SMS faceted browser allows users to browse an annotated dataset by combining the background knowledge extracted from named entities with the inherent attributes of a dataset. The following video demonstrates how the faceted browsing of NEs works:

Data Harmonization

The goal of SMS data harmonization service is to improve the quality and expressiveness of a dataset by enriching it with an existing standard classification. The harmonized datasets can be more easily interlinked with other datasets. For example, with regards to geo data, data can be enriched by adding HASC (Hierarchical Administrative Subdivision Codes) or ISO 3166 country codes. Or with regards to publication/patent data, using FoS (Field of Science), WoS (Web of Science) or IPC (International Patent Classification) classifications.


Geo-enrichment is an instrument to enrich data by linking through geo-location. Many (open) datasets provide variables that are measured at some level of geographical aggregation: e.g., environmental data, educational data, or socio-economic data. In order to exploit these linking and enriching possibilities, the SMS platform provides a variety of geo-services. The geo-services system is based on a series of open geo-resources, such as GADM, OpenStreetMap and Flickr geotagged data. By integrating these geo-resources, the service can give for an entity’s address the geo-location up to 11 different levels. We illustrate this with an example of a service to determine the geographical location if one knows an address (or even only an organization name). As shown in the following figure, in the top right part of the screen the address for “Vrije Universiteit Amsterdam” is inserted, and the application has as output various maps and, in the bottom right, the geo-characterization of the inserted address at eleven levels. The following figure shows the various administrative boundaries for the geocoded address. A simple address-to-boundary application is available, which can be used to check different geo-boundaries used with their corresponding metadata at

With regards to geo-enrichment, SMS provides the following main categories of services:

Geocode a given address.
Find administrative boundaries containing a given point.
Find metadata and details of a given administrative boundary.
Find (multi-)polygon shapes of a given administrative boundary.
Find Functional Urban Areas (FUAs) related to a given administrative boundary.
Connect administrative boundaries to selected statistical data.

One practical application we built for batch processing of addresses is a Google spreadsheet add-on which chains Google Geocoding API with our PointToAdmin and AdminToFUA services. Given addresses in a spreadsheet are enriched with different levels of administrative boundaries and FUAs. The users are then able to export the extracted boundaries and process them in geodata analysis tools such as CartoDB. The following video tutorial demonstrates how to use our Google spreadsheet add-on:

We have also developed a user interface for automatic geo-enrichment of linked datasets in the SMS platform. The interface allows users to select an existing dataset and geocode the whole dataset by selecting the right attributes in the dataset. For a dataset that does not include geo coordinates, addresses will first get automatically geocoded by Google Geocoding API to include longitudes and latitudes. For datasets that are already geocoded, the SMS boundary services will be immediately applied to extract the container boundaries in different levels for existing open geo boundary sources. The result of geo-enrichment can be stored either directly in the original dataset or in a separate dataset with links to original dataset. The interactive user interface allows users to see in real-time the geo-enriched entities on a map with their extracted geo boundaries. For the geo-enriched datasets, users can use the SMS faceted browser to display the entities within the datastes on an interactive map and combine geo-data with other structural attribute of the datasets to facilitate browsing the datasets. The following video demonstrates how the Linked Data geo-enrichment service works :

As another application, SMS proposes a Linked Data approach and implementation which combines openly available spatial and non-spatial resources on the Web to more flexibly classify urban areas. We have already interlinked several datasets related to open geo-boundaries. Users can choose an existing statistical dataset which provides data on certain levels of administrative boundaries and combine it with SMS linked geo data to create a new notion for urban areas. In the section related to use cases, we bring one example of delineating an adaptive urban area.

Data Linking Services and Applications

Before a user can obtain a view over the data of interest, he is to interact with our services. All his/her interactions are of value to the other users in the sense that those actions are documented for others to reuse, modify for different purposes. User interactions include:

Mapping between research question, entity-types and datasets. This enquires about how the research question relates to entity-types hence, datasets that describe those types of interest.
Alignments used to generate linksets. Here, an explicit description of how to align datasets is required from the user.
Lens or user view over the data. The user provides a complete description of how she likes the data to be integrated.
The design of a view. The user submit the set of properties that are of interest to answer her research question.
Link validation. The service requires the user to confirm or reject each correspondence created between entities. The justification of the rejection or validation of a link is asked from the user. The later data is intended to help other users decide on their own whether or not to add a contradictory explanation of why the a previously judged “wrong” link should be reinserted for their particular task.

The following figure shows the steps a user has to take in order to describe and extract a view over the data of interest. For the sake of example, let us assume that the system already contains a set of linksets and lenses. For a user to start a linking activity, she needs a research question. Based on the research question, she is requested to select the entities types of interest, the datasets that describes the selected entity types. From here on, all she needs to do is “Select the lens for the view” and “Design the view”. Once the view is designed, the user uses the linking service to “generate the view table” that she will use for her analysis. After analysing the data, the user is to feed the linking service ”Associate the result of the analyses” with her results (link to publication, report, website...) to finally end the started activity.