Information Infrastructures for managing and providing environmental resources are requested by numerous initiatives on regional, national, and international scales. While much research focuses on the discovery and consumption of provided content, environmental data and model provision is hardly addressed. Each time an expert creates new information or develops a novel scientific algorithm it is delegated to an expert in information and communication technology to make this content available in a given Environmental Information Infrastructure (EII). From our point of view, this workflow is a bottleneck in sharing environmental content that impedes the efficient maintenance of EII. Accordingly, we have extended the classical threelayered EII architecture with a middleware for assisted content publication and deployment. A first implementation for data publishing is in place, while investigations on the publication of environmental models are ongoing. In this position paper, we briefly present the status of our work and discuss possibilities for publishing environmental models. We point to related activities and outline our future plans. We hope that our contribution will help to increase content availability in EIIs in standard basis and thereby will aid content discovery and model composition.
Due to rising challenges of climate change and natural hazards, environmental content
sharing became a central need in environmental sciences [1]. Since many considered
phenomena, such as wild fires, floods or change in biodiversity, cross administrative
borders initiatives for establishing Environmental Information Infrastructures (EII) on
different scales emerged over the past years. Those include Infrastructure for Spatial
Information in Europe (INSPIRE) and Global Monitoring for Environment and
Security (GMES) on European level, and Global Earth Observation System of
Systems (GEOSS) worldwide. An analysis of these three and their interplay has been
published recently [
So far, EIIs assume that only Information and Communication Technology (ICT) experts can provide content as services. This is because current EIIs are based on Service Oriented Architectures (SOA) where services are implemented according to international agreements and standards. The deployment mechanisms imply to understand these standard service specifications and their implementations. ICT experts became the only mediator between the environmental experts, who create the content, and the infrastructure for content sharing [3] [4].
In order to improve the given situation, we suggested extending existing architectures with components and mechanisms, which assist EII users in content deployment [4]. The GEOSS Service Factory (GSF) realizes this proposal. In the next section, we describe the GSF, and point to related work. As we intent to extend GSF with deployment capabilities for (environmental) models, we discuss possibilities and a future stepwise development. We conclude this position paper by summarizing our findings and by outlining our future development plan.
We enable content deployment by adding a (fourth) layer to the classical EII architecture (Figure 1). This middleware layer (GSF, dashed lines in the figure), acts as a mediator to provide content ‘as a Service’ to an EII, which is compliant with INSPIRE and GEOSS. With the GSF, applications became able to push newly created content into EIIs using common formats. Appropriate access services are selected based on content types: Metadata, Data, Model, and Warning.
Applications Workflow Engine Application Logic Service Connector
Applications
Workflow Engine Application Logic Service Connector Metadata
Geospatial Content
Data
Models
Metadata
Geospatial Content Data Models
Warnings It might be noticed that the service layer was extended by Warning Services in order to address upcoming requirements for event notification. Among other information resources, warnings are created in the application layer, for example by spatial decision support systems that integrate available models and execute them on the available data sets. Warning Services are used for managing all warnings that have been published within the EII and distribute according notifications to the EII users. These notifications may follow push or pull based approaches.
In order to provide GSF as a (web) service itself. We decided to use a common
geospatial standard, the Web Processing Service (WPS) [
We designed the GSF using the Abstract Factory pattern from software engineering [8]. The pattern provides a central entry point for content creation/deployment (the Factory), which encapsulated task delegation to specialized deployment components. In this way, the current implementation is easy to extend. As an abstract factory, the GSF holds a group of concrete factories; each of them dealing with a distinct service type and deploying content via transactional service interfaces.
A proof of concept is provided for data deployment in the context of the European
Forest Fire Information System EFFIS [
Much research on model deployment has been carried out, including the Model
Web concept [
At this stage, we remark the following options for model deployment (order indicates
complexity, from simple to most difficult implementation):
1 We have used a generic HTTP client for testing, and a self developed java client [
However, BPMN does not provide information on model semantics. We
propose using a vocabulary, which is shared within the EII community, for this
purpose. It should be available from a shared registry and should be used for
labeling the various BPMN elements.
(2) Deploy executable files to repository. Following the initial ideas of the Model
Web [
In order to make such an implementation usable, we face a model description
problem. We require metadata for model evaluation and use. To make a model
executable, users will require information about: input and output parameters,
required operation systems, versions, and libraries. All may be affected by
licensing issues. Additionally, supported interfaces should be described in a
common manner. Again, descriptions of model semantics are required.
Approaches, such as Web Service Modelling Ontology (WSMO) [
Complementary to the above, we face the practical problem of obsolescence,
i.e. required basic technology or software may simply be outdated and not
available anymore. Open archives try to tackle these problems of long-term
data preservation [
We consider deploying executable process descriptions (using, for instance,
Business Process Execution Language (BPEL)) as a next deployment step. In
this case, chainable service instances have to be available within the EII and
the model has to be provided as an executable process description. For
example, assuming all required data is available as Download Service and each
processing task as a WPS, the complete burned areas calculation workflow
could be made available. A Processing Factory within the GSF would deploy
that script and the composed model will be directly available as a distributed
Processing Service described with WPS interface. The BPEL deployment
functionality of the 52north implementation of WPS [
We believe that the overall solution can only be semi-automatic. For example, only distinct parts of EFFIS can be provided as decoupled processes, due to software packages and dependencies. As for all other options, model semantics still have to be defined in some form of metadata.
We argued that content deployment to EIIs faces complex deployment issues and a central bottleneck in environmental information sharing. The GEOSS Service Factory (GSF) was proposed as a solution. Although the GSF concept is supported by a proof of concept implementation for providing environmental data, detailed elaborations for model deployment remain challenging. We pointed to related research and projects. On this basis, we argued for four possible approaches for model provision. As these complement each other, we plan to address them sequentially. Implementations will be guided by the EFFIS example. The GSF will help to increase content availability in EIIs and thereby will aid information discovery and model composition.
Offering GSF as a service provides means to secure deployment. According implementations may be considered in future. This notably differs from a ‘secure’ execution of models on external machines. The latter is out of the scope of our work.
The presented work was partially founded by EUROGEOSS (FP7-ENV-2008-1226487). The authors thank their colleagues from the Spatial Data Infrastructure Unit of the Joint Research Centre for numerous discussions that shaped the GSF principle. Four anonymous reviewers provided constructive comments for improving an earlier version of this document.