Short description of the WFS standard
The OGC Web Feature Service Interface Standard (WFS) provides a standardized and open interface for requesting geographic features across the web using platform-independent calls. Rather than sharing geographic information at the file level, for example, the WFS offers direct fine-grained access to geographic information at the feature and feature property level. Web feature services allow clients to only retrieve or modify the data they are seeking, rather than retrieving a file that contains the data they are seeking and possibly much more.
WFS operations
The OGC WFS specification support the following operation:
- GetCapabilities - Generates a metadata document describing a WFS service provided by server as well as valid WFS operations and parameters
- DescribeFeatureType - Returns a description of feature types supported by a WFS service
GetFeature - Returns a selection of features from a data source including geometry and attribute values
LockFeature - Prevents a feature from being edited through a persistent feature lock
Transaction - Edits existing feature types by creating, updating, and deleting
GetPropertyValue - Retrieves the value of a feature property or part of the value of a complex feature property from the data store for a set of features identified using a query expression
GetFeatureWithLock - Returns a selection of features and also applies a lock on those features
CreateStoredQuery - Create a stored query on the WFS server
DropStoredQuery - Deletes a stored query from the WFS server
ListStoredQueries - Returns a list of the stored queries on a WFS server
DescribeStoredQueries - Returns a metadata document describing the stored queries on a WFS server
The Role of WFS in SDDI
Currently, the Web Feature Service is in use in the SSD districts London QEOP and Paris Docks de St. Ouen. It allows web-based access to the 3D objects stored in the 3D city database (3DCityDB). WFS clients can directly connect to this interface and retrieve 3D content for a wide variety of purposes. The district model of the Queen Elizabeth Olympic Park includes 3D buildings based on the CityGML LoD2 specification and road footprints also based on the CityGML standard. The district model of Paris Docks de St. Ouen includes 3D buildings based on the CityGML LoD2 specification.
More details about the implementations can be found here.
Standard Specification
Specification documents: http://www.opengeospatial.org/standards/wfs
Implementations / Products
The following selection of products was made by the SDDI team and includes those implementations which are (or likely will be) used in the SSD project and from which we know that they are compatible with the requirements of the Smart Sustainable Data Infrastructure. Please note that the list is not a complete list of available or suitable WFS implementations. The Open Geospatial Consortium provides a catalog of implementations of their standards which can be found at http://www.opengeospatial.org/resource. Note that also the OGC list is not complete and not necessarily completely up-to-date.
WFS service implementations:
| Name | License | Homepage | Short description | Used in SSD districts |
|---|---|---|---|---|
| Geoserver | Open Source | http://geoserver.org/ | Geoserver is a free and open source server for sharing geospatial data. It is an OGC compliant implementation of a number of open standards including Web Feature Service. The current version of WFS is 2.0.0. However, GeoServer supports versions 2.0.0, 1.1.0, and 1.0.0 and supports all the WFS operations. | |
| 3DCityDB WFS Interface | Open Source | https://github.com/3dcitydb/web-feature-service | The 3D City Database WFS interface is implemented against the latest version 2.0 of the OGC Web Feature Service standard and hence is compliant with ISO 19142:2010. Previous versions of the WFS standard are not supported. The implementation currently satisfies the Simple WFS conformance class and does not support additional functionalities (e.g., thematic and spatial filter capabilities and transaction support). The development of the WFS is led by the company virtualcitySYSTEMS GmbH. | |
| virtualcityWFS | Proprietary | http://www.virtualcitysystems.de/en/162-english/products/virtualcitydatabase/extras/221-wfs-2-0-client | virtualcityWFS is developed by the company virtualcitySYSTEMS GmbH. It offers an extended version of the WFS with additional functionalities that go beyond the Simple WFS class (e.g., thematic and spatial filter capabilities and transaction support for inserting, deleting and updating CityGML objects). | London QEOP |
| ArcGIS Server | Proprietary | http://www.esri.com/en/arcgis/products/arcgis-enterprise/overview | ArcGIS Server is the core server geographic information system (GIS) software made by Esri. ArcGIS Server is used for creating and managing GIS Web services, applications, and data. It allows setting WFS and Transactional WFS (WFS-T). |
WFS implementations of clients, interfaces, and libraries required to access and work with a WFS service:
| Name | Type | License | Homepage | Short description | Used in SSD districts |
|---|---|---|---|---|---|
| 3DCityDB WFS Client | Webclient | Open Source | https://github.com/3dcitydb/web-feature-service | The 3D City Database WFS interface provides a client for requesting 3D content across the web using platform-independent calls. | |
virtualcityWFS Client | Webclient | Proprietary | http://www.virtualcitysystems.de/en/162-english/products/virtualcitydatabase/extras/221-wfs-2-0-client | virtualcityWFS also provides a client for requesting 3D content as well as performing transactional operations across the web using platform-independent calls. | London QEOP |
| FME WFS Reader | FME Reader | Proprietary | www.safe.com | FME is a software developed by Safe Software and facilitates the transformation of spatial data into a variety of formats, data models and repositories for transmission to end users. It includes a WFS Reader which allows to define WFS requests and retrieve features. The features, then, can be transformed into a variety of formats and can be used in different applications. | London QEOP |
| QGIS WFS Client | In-built | Open Source | http://www.qgis.org | QGIS is a cross-platform free and open-source desktop GIS application that supports viewing, editing, and analysis of geospatial data. It also supports functionalities to directly load the data from WFS and visualize its features. | |
| ArcGIS Desktop | In-built | Proprietary | http://desktop.arcgis.com | ArcGIS Desktop allows to directly use Web Feature Service (WFS) services as data sources for map layers. Each WFS service may contain multiple data sources. In these cases, each data source will be added as a separate map layer in ArcMap. |
Additional Information
to be provided