Dynamic Quick View, interoperability and the future

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Dynamic Quick View, interoperability and the
future

• Jon Blower, Keith Haines, Chunlei Liu, Alastair
  Gemmell
• Environmental Systems Science Centre
• University of Reading
• United Kingdom

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Introduction

• We have developed an interactive website and map
  server for data visualization
• work originated in UK e-Science programme and
  National Centre for Ocean Forecasting
• Takes advantage of freely-available Web GIS tools
• We have integrated our prototype with the MERSEA
  system (via OPeNDAP)
• not yet an approved MERSEA service
• We hope to demonstrate the exciting potential of
  this system and benefits of adherence to open
  standards
• Will be very important in INSPIRE
• Potential use is much wider than marine science

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Dynamic Quick View (DQV) Service

• Gives very fast previews of 4-D data on an
  interactive website
• Reads data from OPeNDAP servers at the MERSEA
  TEPs
• Draggable, zoomable map
• Allows the fast creation of animations
• Based on a standards-compliant Web Map Service

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Selection of depth
Select from all the depth levels of the model
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Selection of time (range)
Select from all the timesteps in the model
Selection of a time range leads to an animation
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Finding the data value at a point
Click on the data layer, data value and precise
position is shown
Lon -64.08 Lat 36.21 Value 19.27
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Timeseries plots
If a time range is selected, can create a
timeseries plot at a point
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Export to Google Earth

• DQV website contains link to load
  currently-visible data into Google Earth
• Our WMS outputs in KMZ format
• Can then view data alongside other KML datasets
• e.g. DAMOCLES
• Can view animations of data
• No problem with map projections!

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Visualize alongside third-party data

• Hurricane Katrina, August 2005
• Showing sea surface temperature (UK Met Office)
  and storm position/intensity (ECMWF)
• Winds cause upwelling of cooler subsurface water
  on right-hand side of the cyclonic storm track

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Selection of non-MERSEA datasets also available
Everything on the website can be exported to
Google Earth
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The Web Map Service

• DQV website is built on a custom-made WMS
• backwards-compatible with OGC spec, version 1.3.0
• Optimized for fast, dynamic generation of map
  images
• Enhancements to allow changing of colour scale,
  generation of timeseries plots, etc
• Reads data from CF-NetCDF files or OPeNDAP
  servers
• reading directly from NetCDF is more efficient

WMS
OPeNDAP
NetCDF
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Important features of our WMS implementation

• Fast generation of images
• Handling of four-dimensional data
• Handling of data on unusual grids, e.g. NEMO
• Dynamic change of colour scale extent
• Generation of animations
• Export to Google Earth

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Current DQV architecture centralized
NetCDF
NetCDF
NetCDF
TEP 2
TEP 1
TEP 3
OPeNDAP
OPeNDAP
OPeNDAP
WMS
Requires minimal setup Single point of
failure Relies on fast, reliable OPeNDAP servers
DQV website
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Possible future DQV architecture federated
NetCDF
TEP 1
NetCDF
TEP 2
NetCDF
TEP 3
OPeNDAP
WMS
OPeNDAP
WMS
OPeNDAP
WMS
Requires each TEP to install WMS No single point
of failure More efficient
DQV website
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MERSEA data in third-party clients
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In-situ data

• Picture left shows comparison of NEMO model and
  observations for Nov 2004
• Red dots show bad model-obs fits, green dots are
  good fits
• Google Earth allows very efficient browsing of
  these large datasets
• Could do the same for MERSEA systems, e.g.
  CORIOLIS
• Could read obs and model data from different
  sources and bring together in Google Earth or
  another client

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DQV future enhancements

• Display of wind/current fields as vectors
• Caching of image tiles for performance increase
• Support for more map projections
• E.g. polar stereographic
• Display of observations on website
• Integration with GeoServer, THREDDS
• Requires community assistance
• Lots more!

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Conclusions

• We have demonstrated a dynamic website for
  exploring MERSEA data quickly and interactively
• Based on an OGC Web Map Service
• but with important enhancements
• other WMS implementations will not support all
  the features in DQV
• Gives interoperability with third-party services
• view MERSEA data alongside third-party data
• will be important in INSPIRE
• Exciting possibilities for the future!

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Contact details

• jdb_at_mail.nerc-essc.ac.uk
• To find website
• Google for "Godiva2"