Data Circulation and Services in ocean science - Oral ... To make Diva easier to
use, a web interface has been developed. ... Web Server Gateway Interface.
Id = 73 - 2. Data Circulation and Services in ocean science - Oral
A web interface for gridding and visualizing oceanographic data sets Alexander Barth, GeoHydrodynamics and Environment Research (GHER), MARE, AGO, University of Liege, National Fund for Scientific Research,
[email protected] (Belgium) Aida Alvera-Azcárate, GeoHydrodynamics and Environment Research (GHER), MARE, AGO, University of Liege, National Fund for Scientific Research, Belgium, Charles Troupin, GeoHydrodynamics and Environment Research (GHER), MARE, AGO, University of Liege, Belgium, Mohamed Ouberdous, GeoHydrodynamics and Environment Research (GHER), MARE, AGO, University of Liege, Belgium, Jean-Marie Beckers, GeoHydrodynamics and Environment Research (GHER), MARE, AGO, University of Liege, National Fund for Scientific Research, Belgium,
Spatial interpolation of observations on a regular grid is a common task in many oceanographic disciplines (and geosciences in general). Diva (Data-Interpolating Variational Analysis) is an analysis tool for gridding oceanographic in situ data. Diva takes the error in the observations and the typical spatial scale of the underlying field into account. Barriers due to the coastline and the topography in general are also used to propagate the information of a given observation spatially. Diva is a command-line driven application. To make Diva easier to use, a web interface has been developed. The user can directly upload his/her data in ASCII format and enter several parameters for the analysis. The analyzed field, location of the observations, and the error mask are then directly visualized in the browser. While this interface allows the user to create his/her own gridded field, a web interface is also developed to visualize pre-computed gridded oceanographic data sets. Those data sets are typically four-dimensional (longitude, latitude, depth and time). The system allows to visualize horizontal sections at a given depth and time to study the horizontal distribution of a given variable. It is also possible to display the results on an arbitrary vertical section. To study the evolution of the variable in time, the horizontal and vertical sections can also be animated. The user can customize the plot by changing the color-map, the range of the color-bar, the type of the plot (linearly interpolated color, simple contours, filled contours) and download the current view as a simple image or as Keyhole Markup Language (KML) file for visualization in applications such as Google Earth. The system is build using a client and server architecture. The server is written in Python using the Web Server Gateway Interface. The server implements version 1.1.1 and 1.3.0 of the Web Map Service (WMS) protocol of the Open Geospatial Consortium. On the server, all oceanographic data sets are stored as NetCDF files organized in folders and sub-folders allowing for a hierarchical presentation of the available variables. The client is build as a web application using the OpenLayers Javascript library. The web interface is accessible at http://gher-diva.phys.ulg.ac.be/. It is currently used for climatologies created in the frame of the SeaDataNet project and will be used for the EMODNET project (chemical lot). Thrid-party data centers can also integrate the web interface of Diva to show an interpolated field of in situ data as an additional WMS layer.
International Marine Data and Information Systems, IMDIS 2010
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