OSGeo Events, FOSS4G 2008

Font Size:  Small  Medium  Large

Sensor Observation Service from UMN MapServer meets OpenLayer

Till Adams, Dominik Helle

Building: Cape Town International Convention Centre
Room: Kgalagadi Room (Room 2.4b)
Date: 2008-10-02 08:30 AM – 10:00 AM
Last modified: 2008-09-09


Structure of talk
- Introduction
- The SOS specification
- OpenLayers and new layer type SOS-layer
- Live demo of a project from the european alps
- Conclusion

The SOS specification
Sensor Observation Services (SOS) describe standardized web services which allow access to descriptions of associated sensors and their collected observation data.
These sensors can measure environment parameters like temperature, ground motion or short - any parameter featured with any physial signal.
SOS is part of of the OGC's Sensor Web Enablement (SWE) specification. UMN Mapserver supports the SOS specification since version 4.10. Using UMN's SOS interface and
implementing a new layer type called "SOS Layer" in OpenLayers enables us visualizing the sensor data in real-time via the internet.

OpenLayers and new layer type SOS-layer
Core of the project we talk about was the implemenation of a new layer type 'SOS-layer' into OpenLayers (which also will be put back to the developing team of OpenLayers).
In this context we implemented also a so-called 'SOS Manager' as a new control for OpenLayers to enable users to manage multiple SOS servers in the same map. SOS Manager
has a user interface, where several SOS servers could be administered and their layers added to the map. Current Map and Sensor settings can be loaded from old projects and
so also being saved into a new one.
The new OpenLayers SOS framework is able to parse the response from the 'GetObservation' document. This resulting from the GetObservation request is designed to query sensor
systems to retrieve observation data. Specification of observation data is defined in the Observation and Measurement specification (O&M). The framework implementation in the client
visualises mesured data on the map, allows to generate line charts, offers an export interface (csv) and also allows SOS filtering due to the filter encoding (FE) specification.

Live Demo
A combination of wireless sensor networks (WSN), open source databases and web-based geographical information systems has been setup in the Swiss Alps. The observation points,
also called 'nodes' are able to communicate with themselves, share their measured data and hop their measured data from one to the next until an upload gateway is reached.
We call this a self organising, self-healing network. In the actrual example project permafrost data, especially rock temperatures are measured in regions, where permanent
measurement and live access to measured data was not possible before. The question behind is what happens to permanently frozen ground (permafrost) in times of climate change
and how does this affect on slope stability.

In the presentation we will focus on the software technique and use the pilot project to show a short live demo of the system and the OpenLayers integration.