Open GIS WEB services2010-08-30
Open GIS WEB services
OpenGIS Web Services (OWS) are individual components of dynamic geospatial computing applications; they are also parts of an overall paradigm for building solutions to geospatial problems. This paradigm - the Spatial Web - imposes both conceptual and implementation constraints on how OWS works. Conceptual constraints include service orientation, n-tier distribution capability, self-description, and stateless operation; these constraints generally address functionality.
Web Map Services
A Web Map Service (WMS) produces maps of georeferenced data. It defines a "map" as a visual representation of geodata; a map is not the data itself. This specification defines three WMS operations: GetCapabilities returns service-level metadata, which is description of the service's information content and acceptable request parameters.
The NaturNet Redime Mapserver is designed by NaturNet Redime project team and implemented by HSRS (member of CCSS). There is an Open Source technology Mapserver of University of Minnesota. The solution is based on implementation of OGC standards (WMS, WFS), which allow the shareing of data from different servers across Europe. The solution is hosted by servers of CCSS.
Web Feature Service (WFS)
WFS is oriented for vector data exchange on internet. It uses GML format for data transfer. Both geometric and attribute information are transferred with GML. Also OGC Web gazetteer Service profile is derived from this service. An extended capability of the service enables transactional operations like insert/update/delete features on remote server. WFS uses also Filter Encoding for querying.
Web Coverage Service (WCS)
WCS is used for coverage data transfer via internet. This service enables data transfer in native format together with metadata needed for data interpretation. Only raster data are currently supported, vector data are planed to be incorporated in the future. This service plays an important role for satellite data transfer in the system.
Web Processing Service (WPS)
A Web Service Processing Service provides access to calculations or to models which operate on spatially referenced data. The data required by the service can be available locally, or delivered across a network using data exchange standards such as Geography Markup Language (GML) or Geolinked Data Access Service (GDAS). The calculation can be as simple as subtracting one set of spatially referenced numbers from another (e.g. determining the difference in influenza cases between two different seasons), or as complicated as a global climate change model.