Education

OGC Interoperability Day 2008: Ongoing Work

During OGC Interoperability Day in Potsdam, Germany this week, several presentations were given which highlighted some of the activities ongoing within that community.

Thomas Kolbe and Carsten Roensdorf presented on the topic of SIG3D and CityGML. Kolbe is chair of the Special Interoperability Group 3D and CityGML within the OGC organisation.

The group consists of 70 members and contains 3 working groups including interoperability, 3D visualisation and exchange geodata. Founded in 2002 originally in North Rhine Westphalia, Germany these groups meet regularly.

Achievements include:

• CityGML – building a semantic data model and exchange format (which is soon to be adopted internationally)

• Web 3D Service – a real web 3D portrayal service. This service was built before Google Earth came along and included display elements such as VRML97, X3D and U3D. It includes a simulator application named COSIMIR and useful for modeling urban spaces and construction processes.

• ALKIS 3D – based on ISO model and including 3D extensions to interface the German national cadastre model

CityGML as part of the 3D web service has 5 discrete levels of detail (LOD) and includes 3D geometry, 3D topology and semantics as well appearance. As Kolbe says, “ we started with the data model (UML) and went from there. It should not be confused with KML which specific for visual information. CityGML is for developing content.” Conceptually the idea behind CityGML is that the model can be re-used as needed.

Current work includes:

1. Modeling working group

2. Updating and communication

3. ALKIS 3D

Several demo's of CityGML were shown including the statewide model for North Rhine Westfalia, 3D City model of Berlin, Dusseldorf training simulation, 3D City model of Cologne and an example of interoperability involving AEC/GIS.

Roensdorf who works for the Ordnance Survey, UK indicated that that organisation was the first to look at GML. When asked why CityGML he suggested that it provides a way to encode standards for exchange of 3D information but also a means to develop a working 3D city model.

A part of the reason as to why adoption has been slower than expected by mainstream users lies in the fact that many people are not willing to invest in CityGML unless it becomes a standard. “Customers wanted to invest if more security were evident, and standards offer that,” Roensdorf said. “CityGML is a way to offer more semantic richness and there are currently 5-6 software on the market that support CityGML,” he pointed out. It was pointed out that Ordnance Survey reduces the complexity of the model down to 11 primary areas and that the final draft of CityGML specification was nearing readiness.

SANY Sensors Anywhere is a project of the European Union and originated under the 6^th Framework program. The overall objective of SANY is large – to create a single European data space by developing a generic architecture across the member states. This would, ultimately, enable an environmental network that in turn is used to support the emerging sensorweb. As Desiree Hilbring of SANY explained, “it would serve as a discovery mechanism for sensors, related resources, data services, metadata and images.” This in turn would lead to further supporting the GMES and GEOSS programs which are much wider in scope and geography, having international implications.

How will it do this? By incorporating already existing technologies and frameworks based on MASS-SSE, ORCHESTRA, OGC-SWE AND IEEE1451. Hilbring indicated that “people would need to know what they are looking for” when using the service. That is, the status of the project is such that fine resolution of data retrieval is not yet worked out, but she expected that individuals and organisations would likely write more detailed extensions that plug into the overall model, thereby taking advantage of unqiue semantics pertaining to their individual searches.

Patrick Jacques of SANY also presented at the event. His work involves the decision support project whose goal it is to develop reusable components. Capabilities envisioned in his work include;

• discovery of sensor data and services

• access and authentification

• management services

• subscription to visual alarms

• execution processing services

• visualisation of geographic maps

Several Pilot projects involving sensors are currently underway under the workplan.

1. Air Quality Monitoring – cross border monitoring in Belgium/Flanders; fusion mobility service

2. 2) Marine Pilot – quality of bathing water

3. Geo-Hazards Pilot – structural monitoring

Under the SANY / Interoperability banner are efforts related to sensor web enablement, ORCHESTRA IP with a map and diagram service for architectural components and SSE(ESA) for visualisation and web based clients that also involves satellite observation services.

He showed examples of a SOS service from France which exported weather information to Google Earth, an example from Linz, Austria that included temperature information, a demo of the Bay of Gdansk with meteorological information which can describe operators in the processes, units of measurement and the properties of cloud cover. Other examples included soil movement as measured around buildings in Budapest. A fusion service involving SP% and SP6 data included interpolation (kriging) of data points and the user can choose variable output, the service essentially collecting data and geoprocessing it before it would be exported in whatever format was needed.

The SANY initiative would basically result in a common data sensor station across the entire EU. Issues remaining in this approach involve a willingness to join, and that the data might require standard approval. It would involve a plug-and-play system built on IEEE1451 which effectively means it would include 'smart sensors' that know what they are, how to interface electronics and what data to collect.

The German / Indonesian Early Warning System (GITEWS) was presented by Rainer Haner of GFZ – Potsdam. This system is in the early stages of design and will be used to warn residents near coastlines about oncoming tsunami. Haner indicated that only about 20% of all earthquakes fall within the range of possibility for creating tsunami.

Problems with early warning systems include travel times after originating (which are fast) and for southeast Asia this can mean as little as 20-40 minutes. The system can provide a warning within 5 minutes and a stable indication of magnitude. It includes GPS buoys anchored to under water sensors measuring sea pressure, communication interfaces, meteorological instrumentation and a capability to monitor within 300 km of a potential earthquake.

The concept is initiated by the sensors and transferred to satellites then decision support. Challenges of this system are:

• heterogenous sensors

• issues surrounding the network of sensors

• models

• warning system techniques and methods

• actuators

To date the seismic system, ocean instruments, tide gauges, GPS and simulations have been completed. The sustainability of the system is dependent upon service oriented architecture (SOA) and assembly of information which Haner likened to “an assembly line concept where more information adds value as it moves along a processing chain.” A need exists to coordinate a number of different processes and the standardisation of this integration platform would lead to its being enabled. Note: This is a work in progress.

More to come....

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