Sharing and Visualizing Environmental Data using Virtual Globes

© University of Reading 2007 www.resc.reading.ac.uk

11 September 2007

Sharing and Visualizing Environmental Data using Virtual GlobesJon Blower, Alastair Gemmell, Keith HainesReading e-Science Centre, ESSC, University of Reading

Peter Kirsch, Nathan Cunningham, Andrew FlemingBritish Antarctic Survey, Madingley Road, Cambridge

Roy LowryBritish Oceanographic Data Centre, Liverpool

Virtual Globes, e-Science All Hands Meeting 2007

E-Science: Connected science

• We need to be able to connect data across the environmental sciences (right)

• Visualization is very important– But complicated by plethora

of file formats and tools

• Geographic Information Systems (GIS) often complex and vendor-specific

• Environmental science data are four-dimensional– GIS historically focussed on

land surface


How important is visualization?

(Microsoft case study with BP: Hurricane Management System)

• "This solution is changing the way we do business. When the data is presented through a map-based interface, it’s amazing. It gives you a richer, bigger, more intelligent picture of what’s going on. " – Steve Fortune, BP

http://www.microsoft.com/casestudies/casestudy.aspx?casestudyid=201427


The Virtual Solar System

• > 30 Virtual Globes currently available!

NASA World Wind

Google Earth

ArcGIS Explorer

FreeEarthMicrosoft

Virtual Earth


Combining data on a Virtual Globe:Hurricane Katrina, August 2005

• Storm track positions (analysed from ECMWF vorticity data) by Lizzie Froude, ESSC

• Sea surface temperature data from UK Met Office FOAM model

• Combination shows cooling of surface waters on right-hand side of cyclonic storm track

• High winds cause upwelling of cool, deep water


Keyhole Markup Language (KML)

• KML encodes simple geographic features in XML– "Points, lines and

polygons"– Image overlays

• <description> field can hold HTML with links, images etc

• Contains several types of information:– Geolocation– Style– Camera control


Some currently-availableenvironmental datasets in KML format

NERC Centre for Air-Sea Interactions and FluXes

http://www.research.plymouth.ac.uk/casix/

Weather data and storm tracks

http://www.gearthblog.com/blog/archives/2007/06/weather_and_storm_tr.html

UK Met Office ocean forecastshttp://lovejoy.nerc-essc.ac.uk:8080/ncWMS/godiva2.html


Virtual Globes as Discovery andBrowse tools

• BODC uses Google Earth as spatial metadata browsing tool for in-situ measurements

• Can easily check for errors– E.g. ocean data located on

land– Misplaced component of

linear ship track

• Displays “light” metadata, with links to more sophisticated information

• Developed in under a week!


Real-time data visualization

• British Antarctic Survey (BAS) used KML data feeds to support 2 scientific cruises in 2006

• Multiple data streams (ship location, sea temp and salinity, air temp and pressure) streamed to Google Earth in near real time

• Enabled real-time decision-making (e.g. tracking of predators, left)

• Saved ship time, hence £££King penguin track

overlain with concurrent chlorophyll and satellite

imagery


Beyond visualization:Extending the capabilities of VGs

• Approach 1: Extend the client– Only possible if VG exposes an API or is open source– ArcGIS Explorer (.NET API)– NASA WorldWind (Java API, Open Source)

• Approach 2: Do processing on a server– Expose results as KML via a Web Service– Can use web interface to control the Web Service– Useful for closed-source systems (e.g. Google Earth)


Example: ocean data assimilation

• Scientists need to compare ocean models and observations

• A Web Service performs comparison, then outputs results in KML

• Red dots show bad model-obs fits, green dots are good fits

• Clicking on an observation brings up more information

• Driving real improvements in the model

http://www.nerc-essc.ac.uk/~alg/OceanDIVA.html


Virtual Globes: pros and cons

• Pros:– Easy to use– Easy data formats– Compelling visualizations

• Cons:– Generally no data

analysis functions– Vertical and temporal

dimensions not always handled properly (left)

– Patchy support for OGC Web Services

• (But products vary widely)

Vertical structure of Gulf Stream shown above sea level in Google Earth


What is the best scientific use for VGs?

Have an idea Discuss/explore Do the work Publish

Virtual Globes

MATLAB, IDL etc


Alternatives to Virtual Globes: WebGIS

• Lots of systems now available for displaying geographic data on the Web– Google/Yahoo Maps– Microsoft Virtual Earth– OpenLayers– FreeEarth– WorldKit

• Usually based on Javascript API

• Usually read imagery from map tile services

• Can often overlay simple features (KML, GeoRSS)

ICEDS (UCL)

Godiva2 (ReSC)


Did Hurricane Felix cause the seasurface to cool?

• Storm track from www.hurricane-tracking.co.uk

• Sea surface temperature from OSTIA (analysed satellite product), UK Met Office

• Little visible evidence of cooling.

• Why different behaviour from Katrina?

http://gearthblog.com/blog/archives/2006/07/weather_and_sto.html

http://lovejoy.nerc-essc.ac.uk:8080/ncWMS/godiva2.html?dataset=OSTIA&variable=analysed_sst

http://ghrsst-pp.metoffice.com/pages/latest_analysis/ostia.html


Beyond KML:Geography Markup Language (GML)

• KML ≈ GML v2 (simple features)

• GML v3 adds much more sophistication (complex features)

• Communities create profiles of GML ("Application Schema")– Describes features of

interest

• NERC Data Grid created CSML– Climate Science Markup

Language

ProfileSeriesFeature

ProfileFeature

GridFeature

Thanks to Andrew Woolf (STFC and NDG)


Open Geospatial Web Services

• Open Geospatial Consortium publishes open standards for geospatial Web Services:

(plus many more!)

Web Coverag

e Service

Gridded data(NetCDF, GeoTIFF)

Web Map

Service

Map imagery(PNG, JPG, GIF)

Web Feature Service

Features(GML)


Importance of sharing geospatial data

• "Approximately 80% of business and government information has some reference to location, but until recently the power of geographic or spatial information and location has been underutilized as a vital resource for improving economic productivity, decision-making, and delivery of services" – OGC vision

• EU INSPIRE directive mandates that all public bodies must provide:– Discovery services– View services– Download services


What I haven't discussed

• Security– Need solution based on simple HTTP GET

• Licensing

• Public outreach


Summary• Virtual Globes allow easy simultaneous visualization

of lots of types of environmental data• Well-suited to "exploratory" phases of scientific work• Good way for data providers to advertise their wares• KML is simple but limited way of encoding data

– It's a visualization format really

• GML should be used to encode data for true interoperability– But needs concerted community effort to define feature types

• Simple interfaces are good!– "scriptability" enables mashups


Also see …• Reading e-Science Centre booth• Satoshi Sekiguchi, "GEO Grid"

– Keynote, Tuesday 09:45

• Tim Foresman, "Digital Earth: The New Digital Commons"– Keynote, Wednesday 15:00

• Gen-Tao Chiang, "Driving Google Earth from Fortran"– Session 2.2, Tuesday 15:10

• Gobe Hobona, "Workflow enactment of grid-enabled geospatial Web Services"– Session 3.4, Wednesday 11:25

• Geolinking demo, White Rose Grid– Demo session, Wednesday 14:30

• E-Science Highlights, Issue 2 (in your delegate pack!)

Sharing and Visualizing Environmental Data using Virtual Globes

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