O3S

Open-standard Online Observation Service

The project Open-standard Online Observation Service (O3S), performed under European Space Agency Contract No. 4000101552/10/I-AM, has addressed the evaluation and demonstration of Open Geospatial Consortium (OGC) Web Services, in particular of areas where the Web Coverage Service (WCS) and the Web Map Service (WMS) technologies can bring benefits to satellite Earth Observation (EO) Payload Data Ground Segments (PDGS) and to users. These areas include, for example, online data access and provision of value added products.

The standards frame for O3S is the Heterogeneous Mission Accessibility (HMA) initiative which is building upon such OGC standards and includes EO-specific profiling related to online data access and security aspects.

WCS permits innovative "coverage-oriented" views into satellite data archives and is an alternative to traditional scene- or file-based data access. EO-WCS, the Earth Observation Application Profile of WCS, is designed to enhance the usability of satellite data supplies by providing retrieval of archived data which reside exactly inside user-specified parameter ranges, typically the geographic area and time of interest. WCS encapsulates the complexity of satellite-specific orbital patterns, sensor geometries, data acquisition peculiarities, and custom storage formats. WCS avoids tedious unpacking, clipping, decoding, and reformatting of downloaded data by delivering user-selected content and representations. WCS therefore makes it easier to build user-side functionality like automated higher-level product generation processing and to support interactive data exploitation applications like QGis or ArcGis with raster data import. Please follow this link for further information about WCS and EO-WCS.

O3S was jointly conducted by EOX IT Services GmbH (Austria), Austrian Institute of Technology (Austria), ANF Data (Czech Republic), Iguassu Software Systems (Czech Republic). Further Peter Baumann from the Jacobs University Bremen acted as consultant to the project in Open Geospatial Consortium (OGC) and especially Web Coverage Service (WCS) related questions.

The O3S project delivered new Open Source software for controlled Web-based Earth Observation satellite data access and selected representative demonstrations of the software potentially of interest to the implementers of future ground infrastructure. O3S results are fully in-line and augmenting the standards of the ESA coordinated HMA (Heterogeneous Mission Accessibility) initiative.

Schedule

The O3S Software System is conceived as a collection of Open Source Software (re-used as well as newly developed in the O3S Project) for controlled Web-based access to geospatial data archives ("online data access").
It is expected that by installing the O3S Software System the operators of EO satellite information infrastructures will gain advantages through:

• easy integration of geospatial data archives with end-user applications, meaning less system implementation, roll-out and maintenance costs;
• service compliance with standards, meaning openness for future evolutions and international interoperability.
• improved bandwidth use.

The Heterogeneous Mission Accessibility (HMA) initiative is the main reference and standards frame for the O3S Software System and the services provided/enabled by the system. HMA is built upon OGC standards and includes EO specific contributions related to online data access and security aspects stemming from the ESA project "HMA-FO Task3". The O3S project is contributing Beta version software as Reference Implementations which can be instantiated also during future HMA implementations such as – for example on the ESA side – the GMES Data Access Interoperability Layer (DAIL).

The O3S Software System consists of the following Subsystems:

1. The O3S Server
2. The O3S Identity Management
3. The O3S Applications Interface

The O3S Software System Subsystems are implementing O3 Services which are provided to external applications (e.g. to a decision support tool requiring information derived from EO imagery). This application may either use the O3S directly as standardized Web services or integrate them via the custom O3 Application Programming Interface.

Via the O3 Services the application is enabled to consume storage resources (e.g. provided within an EO satellite mission's PDGS) without knowledge how these resources are organized, called-up, and how they may need to be combined in order to deliver the desired result. This knowledge is implemented within the O3S Server.

The O3S Software System additionally provides appropriate authentication and authorisation means via the O3S Identity Management subsystem.

The Open Source software development which was progressed mainly during the O3S project is called EOxServer. Quoting from the EOxServer web page:
EOxServer's mission: To provide an Open Source software framework to ease the online provision of big Earth Observation data archives via Open Standard services for efficient exploitation by users.

• Open Source: MIT-style license
• software framework: Entirely based on Open Source (Python, MapServer, Django, GDAL, etc.)
• ease online provision: Admin GUI and command line data registration
• ''big Earth Observation data archives: Operators register existing raster data archives'
• Open Standard services: Open in the sense of freely available; Open Geospatial Consortium (OGC); WMS, WCS, EO-WMS, EO-WCS
• efficient exploitation by users: User defined sub-setting; view and download

The screen shot below shows the joint EO-WMS, EO-WCS exploitation in UC3.

Screen shot of the joint EO-WMS, EO-WCS exploitation in UC3

In the frame of the O3S project the following three Demonstration Use Cases (UC) have been defined with the main scope to prove the expected advantages and to show in detail the usage of the O3S Software System:

• O3S UC1: ENVISAT ASAR Referenceable Grid Coverage Download
• O3S UC2: Pléiades HR Rectified Stitched Mosaic Download
• O3S UC3: IMAGE2009 Rectified Grid Coverage Download

Also in the frame of the O3S project the team participated in OGC's Web Services, Phase 8 (OWS-8) and the GEOSS Architecture Implementation Pilot (AIP-4). The outcome of both participations can best be reviewed by watching the videos for OWS-9 and AIP-4 which the team produced.

Various presentations about the results of O3S have been already given and will be given in future:

• AGIT 2011, Salzburg - Introducing WCS 2.0, EO-WCS, and Open Source implementations (MapServer, rasdaman, and EOxServer) enabling the Online Data Access to Heterogeneous Multidimensional Satellite Data
• FOSS4G 2011, Denver - WCS in MapServer 6.0
• GEO Plenary 2011, Istanbul
• HMA-AWG 2012, ESA ESRIN - WCS Standardization & Reference Implementation
• FOSSGIS 2012, Dessau - EOxServer, GDAL, MapServer - Zugang zu großen Archiven von Erdbeobachtungsdaten
• Linuxwochen 2012, Wien - EOxServer & Mapserver - Open Source Lösungen für Erdbeobachtungsdaten
• FOSS4G-CEE 2012, Prague EOxServer: A Solution for Online Access to Large Collections of Earth Observation Data

Note that most of the presentations can be downloaded form the EOxServer documentation.

Highlights:

• The O3S team is proud of having substantially contributed to the 0.2.0 release of EOxServer available since 4th May 2012.
• Uptake of O3S developed software has taken place by various projects like ((DREAM|DREAM), EarthServer, CryoLand, etc.

Deliverables

Please follow this link to download approved O3S deliverables.