4 Final Report - Emits - ESA

4 Final
Report
is mandatory to take into account not only existing but also evolving standards, which are commonly
agreed not only in the remote sensing domain but also within a broad community of Geo Information
Service providers and users. Utilising standards guarantees interoperability between different systems
and a unified access to these from a user point of view.
At present, the Open Geospatial Consortium (OGC) is the most relevant entity which defines and
drives the relevant open standards. Within the OGC, the Sensor Web Enablement (SWE) focuses on
sensors and sensor networks. The definition of the SWE standards aims to access and, where
applicable, to control all types of sensors, instruments and imaging devices via the Web.
For this purpose, the SWE comprises seven major elements, i.e.:
(1) Observations & Measurements Schema (O&M) – Standard models and XML Schema for
encoding observations and measurements from a sensor, both archived and real-time.
Current standard: OGC 07-022r1 Observation and Measurements – Part 1 – Observation
Schema
(2) Sensor Model Language (SensorML) – Standard models and XML Schema for describing
sensors systems and processes; provides information needed for discovery of sensors,
location of sensor observations, processing of low-level sensor observations, and listing of
taskable properties.
Current standard: OGC 07-000 Sensor Model Language
(3) Transducer Markup Language (TransducerML or TML) – The conceptual model and XML
Schema for describing transducers and supporting real-time streaming of data to and from
sensor systems.
Current standard: OGC 06-010r6 Transducer Markup Language
(4) Sensor Observations Service (SOS) - Standard web service interface for requesting, filtering,
and retrieving observations and sensor system information. This is the intermediary between
a client and an observation repository or near real-time sensor channel.
Current standard: OGC 06-009r6 Sensor Observation Service
(5) Sensor Planning Service (SPS) – Standard web service interface for requesting user-driven
acquisitions and observations. This is the intermediary between a client and a sensor
collection management environment.
Current standard: OGC 07-018 Sensor Planning Service Application Profile for EO Sensors
(6) Sensor Alert Service (SAS) – Standard web service interface for publishing and subscribing
to alerts from sensors.
Draft standard (not yet released): OGC 06-028r5 Sensor Alert Service
(7) Web Notification Services (WNS) – Standard web service interface for asynchronous
delivery of messages or alerts from SAS and SPS web services and other elements of
service workflows.
With relation to the "Inspire" directive of the EC, which aims at establishing a Geo-data infrastructure
for Europe, the OGC specifications are the key drivers for defining the standardised exchange of Geoinformation
within the European Community.
As can be seen from the above considerations, the realisation of the user portal following the OGC
standards allows to define generic user requests via the Web, where user requests can be among
others:
• Catalogue browsing (primarily the request/mission catalogue)
• Image requests from the archive and re-processing requests of archived data
• Performing new acquisitions (routine and emergency)
• Monitoring of events and submittal of alerts and notifications
Apart from the above-mentioned user services, the user portal is also in charge of handling all related
Doc. No: GOC-ASG-RP-002 Page 4-83
Issue: 2
Date: 13.05.2009 Astrium GmbH