=Paper=
{{Paper
|id=Vol-1762/Pesquer
|storemode=property
|title=RiBaSE: A Pilot for Testing the OGC Web Services Integration of Water-related Information and Models
|pdfUrl=https://ceur-ws.org/Vol-1762/Pesquer.pdf
|volume=Vol-1762
|authors=Lluís Pesquer Mayos,Christoph Stasch,Simon Jirka,Joan Masó Pau,David Arctur
}}
==RiBaSE: A Pilot for Testing the OGC Web Services Integration of Water-related Information and Models==
https://ceur-ws.org/Vol-1762/Pesquer.pdf
RiBaSE: A Pilot for Testing the OGC Web Services
Integration of Water-related Information and Models
Lluís Pesquer Mayos, Simon Jirka,
Grumets Research Group CREAF 52°North Initiative for Geospatial Open Source Software
Edicifi C, Universitat Autònoma de Barcelona GmbH
08193 Bellaterra, Spain 48155 Münster, Germany
l.pesquer@creaf.uab.cat s.jirka@52north.org
Christoph Stasch, Joan Masó Pau,
Grumets Research Group CREAF
52°North Initiative for Geospatial Open Source Software
Edicifi C, Universitat Autònoma de Barcelona
GmbH
Bellaterra, Spain
48155 Münster, Germany
joan.maso@uab.es
c.stasch@52north.org
David Arctur,
Center for Research in Water Resources,
University of Texas at Austin
10100 Burnet Rd Bldg 119, Austin, TX USA
david.arctur@utexas.edu
Abstract—The design of an interoperability experiment to The OGC is an international industry consortium of
demonstrate how current ICT-based tools and water data can companies, government agencies and universities participating
work in combination with geospatial web services is presented. in a consensus process to develop publicly available interface
This solution is being tested in three transboundary river basins: standards. Some successful examples of OGC standards for
Scheldt, Maritsa and Severn. The purpose of this experiment is to general spatial purposes are, for example, the Web Map
assess the effectiveness of OGC standards for describing status Service (WMS) for providing interoperable pictorial maps
and dynamics of surface water in river basins, to demonstrate over the web and the Keyhole Markup Language (KML) as a
their applicability and finally to increase awareness of emerging data format for virtual globes. On the other hand,
hydrological standards as WaterML 2.0. Also, this pilot will help
specializations of common OGC standards for the water
in identifying potential gaps in OGC standards in water domain
domain, such as WaterML 2.0, a model and exchange format
applications, applied to a flooding scenario in present work.
for water observations and metadata, are not yet as widely
Keywords—Interoperabilty; WaterML; flood modeling; river used as the veteran WMS standard. Hence, supporting tools
basin management; OGC; WPS such as an official WaterML validator are not yet available [1]
in the OGC compliance program [2]. Notwithstanding, some
I. INTRODUCTION current efforts are progressing in this sector, e.g. the Sensor
There are several standardization committees and Web Enablement (SWE), where the corresponding working
international organizations relevant for water domain group develops standards to integrate sensors into the
Information Technology (IT) applications: International Geospatial Web [3]; and a second example is the WMO
Organization for Standardization (ISO), World Wide Web Hydrology Domain Working Group that close collaborates
Consortium (W3C), Institute of Electrical and Electronics with the World Meteorological Organization (WMO)
Engineers (IEEE), Organization for the Advancement of Commission for Hydrology [4]. Furthermore, the level of
Structured Information Standards (OASIS), Open Geospatial interoperability that may be achieved using these standards in
Consortium (OGC), Internet Engineering Task Force (IETF), different application scenarios and study areas has not yet
etc. Related to the Infrastructure for Spatial Information in been fully evaluated, specifically the lack of interoperability
Europe (INSPIRE), the OGC is one of the main players (with between information provided by sensors and the processing
the ISO TC211) providing standardized specifications of services and alerts.
spatial information and interoperability of the corresponding European directives such as INSPIRE, the Water
spatial data services. Framework Directive (WFD), or the EU Floods Directive
(Directive 2007/60/EC), as well as agendas and roadmaps The whole approach is shown in Figure 1 including the
include many recommendations in terms of harmonization, services involved and the client interfaces. Essentially, the
standardization and interoperability goals. They indeed raise monitoring of meteorological data and the hydrological gauges
very important challenges for progressing in these issues. In provide input data to a flood prediction model. Depending on
particular, the water sector needs standards for: countries and agencies, the data is provided in heterogeneous
structures and formats, e.g. as plain CSV files or in custom
• Exchange of geographic information at local, regional and XML formats. In order to ease the integration of different data
global levels. sources, the Observation & Measurements (O&M) standard
• Transmission of hydrological information to different and its extension for WaterML 2.0 defines common models
agencies and organizations. and encodings for observation data. In case data inputs are not
yet provided in WaterML 2.0 or O&M, a translator component
• Dissemination of hydrological forecasts between different is needed that allows conversion of the data into the WaterML
agencies and corresponding own methodologies. 2.0 structure for providing it via Sensor Observation Services
• Alerting and Notification between data and model (SOS) or netCDF format in a Web Coverage Service (WCS).
providers and decision makers. The flood model (detailed in the next section) is encapsulated
in a Web Processing Service (WPS) allowing the execution of
Flood modeling is a paradigmatic example in the water it in Web-based infrastructures. The output of the model is
domain where standardization can improve the IT sent to a client for visualization purposes under a WMS and
contributions to the society. The increasingly variable climate the raw data can be downloaded via a WCS service or Web
has seen a rising number of extreme flood events in the last Feature Service (WFS), which is transactional for a better
decades. Floods are natural phenomena that cannot be fully integration with WPS. These services are launched by the
avoided, but through the right measures we can reduce their WPS client that controls the status of the WPS and coordinates
likelihood and limit their impacts. Indeed, floods pose great its outputs and the following processes. At the end of this
challenges to decision makers of the meteorological and workflow and, in case of a risk situation for a particular
hydrological agencies and local communities. An location in a river basin, an alert notification will be sent.
interoperable design of all related components in the area of Since there is not yet a common standard available for the
flood forecasting, warning, and emergency response will alerting functionality, new concepts such as encapsulating the
contribute to the integrated flood management plans on event engine in WPS are being elaborated and tested in the
various administrative scales. pilot. In this architecture, the client applications enable
In the context of the Horizon 2020 project WaterInnEU 1 control, visualization and decision support based on the model
and coordinated by the OGC, an Interoperability Pilot, called results, considering data and metadata.
RiBaSE, is designed for testing:
• the adaptability of common spatial standards to water
applications
• the best suitable connection between them
• the specific characteristics for the engaging of the
WaterML 2.0 in a general geospatial framework.
While there are many examples of data management and
modeling systems as separate tools in the water domain, fewer
examples of integrated systems are set up. The present work
follows the general trend towards standardization in both the
data and the modeling [5]. This paper describes the overall
approach of this pilot, key standardization issues, and
corresponding solutions for a global interoperable workflow
for supporting decision makers in an inland flood risk
situation.
II. INTEROPERABILTY PILOT DESIGN Fig. 1. Pilot workflow
The present work aims to design a global approach for one Short descriptions of the standards utilized in these
hydrological issue, an emergency flood scenario, integrating components are as follows (references to these standards are
all related processes in an interoperable way. Previous works given in Table 1):
such as [6] and [7] have demonstrated the possibilities for the
NetCDF – Network Common Data Form: It consists of a
integration of some hydrological applications with OGC
standards suite that supports encoding of digital geospatial
standards, however a complete interoperable workflow (from
information representing space/time-varying phenomena in a
the primary data sources, to final outputs, including all
binary file format.
processing models) still needs to be designed and developed.
SAS – Sensor Alert Service: It is an event notification
1
http://www.waterinneu.org service for determining the nature of offered alerts, the
protocols used, and the options to subscribe to specific alert The general workflow that integrates all these components
types. in a flooding scenario is structured in four concrete
experiments:
SOS – Sensor Observation Service: It defines a Web
Service interface which allows querying and receiving • Experiment #1: Extract WaterML 2.0 from the SOS
observations, sensor metadata, as well as representations of 2.0 Hydrology Profile for the desired area and time.
observed features.
• Experiment #2: If the readings exceed a threshold,
WaterML 2.0: It is a standard information model for the start a WPS 2.0 execution with a hydrological model.
representation of in-situ water observation data. In fact, it is a
specialization of a more generic standard: ISO/OGC • Experiment #3: Expose the results of the model using
Observations & Measurements. So far, WaterML 2.0 is geospatial services to download data suitable for
composed of three parts: Part 1: Time series; Part 2: Ratings, visualization.
Gauging and Sections; Part 3: Water Quality. This work • Experiment #4: Notify alerts to the relevant
primarily uses Part 1. emergency services using Sensor Notification
WCS – Web Coverage Service: It defines a standard Services or similar. This might be more experimental,
interface and operations that enable interoperable access to since there is a lack of official standards. Current work
geospatial grid coverage. of the OGC Pub/Sub Standards Working Group can be
an alternative to take into consideration.
WFS – Web Feature Service: It defines a Web interface
with operations for querying and editing vector geographic Some recommendations for the suitable integration of the
features. The subtype WFS-T (transactional) allows creation, four experiments into the whole workflow need to be
deletion, and updating of features. considered:
WPS – Web Processing Service: It is a standardized Related to Experiment #1, the SOS can be used to query
interface that defines a standardized Web-based access to O&M data and metadata about sensors in a standardized way.
geoprocessing functionality, as well as rules for standardizing A specialization of the SOS for the water domain already
the inputs and outputs (requests and responses) of geospatial exists with the SOS Hydrology profile [9]. Hence, the pilot
processing functionality. This is the main component for the can evaluate the application of the SOS Hydrology profile.
flood model and this solution has been successful for The threshold for Experiment #2 is being recalculated for each
geoprocessing in other water resource systems [8]. study region considering the statistics of the previous
The services considered in this workflow can be classified executions.
by their main functionality as: In Experiment. #3, input data (as well as output data) also
• Data exchanging: NetCDF and WaterML translator needs interfaces to be published over the web: stream gauge
data and a time series hydrograph (WMS) and gridded data
• Modeling: WPS flood simulation (WCS) are forms suitable for publishing the time series graph
and map data.
• Delivering: WCS (raster), WFS (vector), SAS (alerts)
For Experiment #4, various notifications are triggered
• Visualization: WMS (maps) depending on the location, timing, and severity of the alert
situation.
Acronym Standards Specifications III. MODEL IMPLEMENTATION
netCDF CF www.opengeospatial.org/standards/netcdf The model to predict and map inland flood inundation
areas is the core component of the RiBaSE architecture. This
SAS draft www.opengeospatial.org/projects/initiativ architecture allows any execution model with a complete
es/sasie description of all processes, options, variables and parameters
involved. This description allows a generic WPS implemented
SOS 2.0 www.opengeospatial.org/standards/sos solution and models from AutoRapid [10], TauDEM 2/HAND
WaterML 2.0 www.opengeospatial.org/standards/water [11] or r.inund.fluv (GRASS) [12]. The WPS descriptions are
ml encapsulated in a XML file (example in Fig. 2) containing all
WCS 2.0 www.opengeospatial.org/standards/wcs the necessary information for server execution.
WFS 2.0 www.opengeospatial.org/standards/wfs
WPS 1.0 www.opengeospatial.org/standards/wps
Table 1. Where to find the complete information corresponding to the OGC
standards referred to in the architecture diagram
2
http://hydrology.usu.edu/taudem/taudem5/index.html
Fig. 4. Flood Prediction interface from a 52°North client
Fig. 3. First content of WPS ProcessDescription XML file
This complete description is the key for the correct IV. CASE STUDIES
interpretation and implementation of the main WPS operations In order to test the present design, three transboundary
(shown in Figure 3): regions have been proposed: Scheldt, Maritsa and Severn.
• GetCapabilities: it describes the service and provides the Figure 5 shows a short geographical description for these
list of available processing functionality in the instance. areas.
• DescribeProcess: it is a full description of inputs and
outputs of a specific geoprocessing functionality, e.g.
parameter names, value types, what parameters are
optional or mandatory, default values, etc.
• Execute: it runs a process with the inputs provided and
returns the corresponding outputs
Fig. 3. Workflow of the main operations between WPS server and the
corresponding client Fig. 5. Map location of the three case studies, red polygons over Blue Marble
NASA-JPL image
For this pilot, the WPS is implemented on the server side
The Scheldt flows through Wallonia, Flanders and the
as a Common Gateway Interface (CGI). Thus it is enabled for
Netherlands, and discharges in the North Sea at Flushing. This
wrapping the selected hydrological model and guided by the
makes it one of Europe’s most densely populated river basin
WPS configuration file. The WPS client instance implemented
districts. The hydrological dataset has been downloaded from
is provided by 52°North 3 (Figure 4).
the portal of the Flemish Water Management 4 in WaterML 2.0
format.
Maritsa is the largest river in Balkan Peninsula and flows
through Bulgaria, Greek and Turkey. A small subsample of
data for this study is provided by the East Aegean River Basin
in a CSV format.
The Severn rises on the northeastern slopes of Plynlimon
(Wales) and flows to the Bristol Channel and the Atlantic
3 4
http://52north.org www.waterinfo.be
Ocean. It is the longest river in the United Kingdom. It is Future works will aim to conduct the same architecture
about 354 km long and its drainage basin area is 11266 km2. with other flooding models and using finer (spatial and time)
The hydrological dataset is provided by the National River resolution datasets and examine the expected improvements
Flow Archive (NRFA) through a SOS hosted in the Centre for on the accuracy of predictions.
Ecology & Hydrology (CEH) 5 (Figure 6).
In these three regions, the terrain is obtained from the
ASTER Global Digital Elevation Model 30 m spatial ACKNOWLEDGMENT
resolution [13]. This resolution is enough for testing the This work is currently developing within the WaterInnEU
interoperability challenges in present experiment, but a finer project (No 641821) that has received funding from the
resolution would be needed for a more accurate European Union’s Horizon 2020 research and innovation
implementation. Other main auxiliary information, also non- programme and it is also supported by Catalan Government
time dependent in this study, is the land use database: under Grant 2014SGR-149.
CORINE Land Cover [14] (available for Bulgaria and Turkey,
but not for Greece in Maritsa). Since both data sets are not
dynamic, interoperability efforts are not strictly necessary.
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5
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