Transcript Maarten Plieger

OGC Web Services
Data visualization using
OGC web services
Maarten Plieger
Wim Som de Cerff
Royal Netherlands Meteorological Institute (KNMI)
R&D Information and Observation Technology
EURO4M Project Kick-Off, April 2010
EURO4M Project Kick-Off, April 2010
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Introduction
Web Services from the Open Geospatial
Consortium (OGC)
Web Map Service (WMS)
Web Coverage Service (WCS)
WMS/WCS portal and server (ADAGUC)
Styled layer descriptors (SLD)
GIS clients supporting WMS/WCS
Application of OGC services in EURO4M
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Introduction to OGC services
OGC – Open Geospatial Consortium (www.opengeospatial.org)
currently ~400 organizations
standards for geospatial content and services
GIS data sharing and processing
Services used within the ADAGUC project:
ADAGUC: Atmospheric Data Access for the Geospatial User Community, was finished in 2009)
Web Map Service (WMS)
- for images
Web Feature Service (WFS)
- for vector data
Web Coverage Service (WCS) - for raster data
WMS is primarily for visualization
WFS and WCS are for retrieval of data, respectively features and
coverages
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Web Map Service - WMS
A WMS is used to generate visualizations of geospatial data in the
form of 2D images suitable for transfer over the World Wide Web
2 metre temperature (K)
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Web Map Service - WMS
A WMS is able to re-project and transform geospatial data to
other projections
Web Map Services from different sources can be combined to a
single presentation
Original data stays at the source, WMS is purely a visualisation
Just images are transferred; network usage is relatively low
(compared to transferring data files)
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WMS Servers
Images
WMS client
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WMS Requests - overview
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Web Coverage Service - WCS
Similar to WMS, but returns data instead of visualizations
Returns observations in a regular spaced grid
Provides data in geotiff, ascii, netcdf, HDF5, etc…
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Software for WMS and WCS: ADAGUC Server
Developed for making the KNMI precipitation radar available in OGC
services (March 2009)
Maintained and extended during other projects
Features:
WMS 1.0 and WMS 1.1.1 (visualization)
WCS 1.0 (data)
Supports Time dimension and real-time update of data
Proj.4 projection strings in getmap requests
Uses GDAL for WCS output
Animated gif
Support for named Styles: bilinear interpolation and contouring/shading
Suitable for all raster ADAGUC files (NetCDF 3/4 with CF)
Uses PostgreSQL database to keep track of available data
Configurable by XML files
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Web Portal (from ADAGUC)
WMS GetMap
WMS GetCapabilities
WMS
GetFeatureInfo
WMS
GetLegendGraphic
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GIS clients supporting WMS and/or WCS
ArcGIS Explorer
gvSIG
Google Earth
ArcGIS Desktop
IDV
Quantum GIS
UDIG
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Styling using Styled Layer Desriptors (SLD)
Styling of sea level pressure (psl) using customizable styles
style=default
style=psl/bilinear
style=psl/shadedcontour
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OGC services in other projects at the KNMI
Rheinblick Hyras interpolation project
Interpolated datasets are made available using OGC services
KNMI weatherstation web application
Uses the KNMI precipitation radar WMS
Meteosat Second Generation (MSG) KNMI products
Will be converted to the ADAGUC data format and made availabe in OGC
services
IS-ENES
Climate model data will be made available in OGC services (DEMO)
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Possible application of OGC services in EURO4M
The OGC services presented here are suited for:
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Combination of Web Map Services from different sources
Retrieval of geospatial data in a GIS compatible format
Viewing maps interactively on a web page
» Maybe part of a web climate bulletin?
Currently less suited for:
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Final presentation in a climate bulletin paper
» Use existing tools for final editing
“Ideal situation”
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Each participant provides his data using OGC services
Data from all participants can be displayed and combined in a portal
Anybody is able to use data from these OGC services for his own
analysis and algorithms
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Possible data format for EURO4M: NetCDF4-CF
•NetCDF4 with Climate and Forecast conventions (CF conventions)
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Standard names, standard units (http://cf-pcmdi.llnl.gov/documents/cf-standard-names/)
Identify and compare data
Locate data in space–time as a function of other independent
coordinate variables (time, latitude and longitude):
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Questions and/or discussion?