Spatial Data Access Tool:

Yaxing Wei, Suresh-Kumar Santhana-Vannan, Robert B. Cook, Bruce E. Wilson, and Tammy W. Beaty weiy@ornl.gov

Oak Ridge National Laboratory

December 14th 2009

Enable visualization and access of geospatial data using OGC services and Google Earth

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ORNL DAAC

• Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC)– NASA-sponsored source for biogeochemical and

ecological data and models useful in environmental research

• Data in ORNL DAAC– field campaign, land validation, regional and

global data– over 800 data sets, ~220,000 files, ~1.1TB size– various formats

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MAST-DC

• The Modeling and Synthesis Thematic Data Center (MAST-DC)– provide data management support for North

American Carbon Program (NACP) project– provide data to users in the formats, resolutions,

and projections based on their requirements• Data in MAST-DC

– model inputs, model outputs, observations (forest/crop, tower flux), and other related data

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Challenges faced by data centers

• Rapidly increasing archiving rate• Heterogeneity of geospatial data• Rapidly growing user community and user

requirements• Heterogeneity of data delivering mechanism

– Diverse ways in which data centers publish and deliver geospatial data introduce extra burden to users to access data from multiple data centers

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New solutions needed!

• Data users need to:– Find and visualize data efficiently– Access diverse data in ready-for-use formats– Access diverse data in a standard way

• ORNL DAAC and MAST-DC have tapped into the benefits offered by Open Geospatial Consortium (OGC) standards, Web-enabled GIS tools, and Virtual Globe technology.

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OGC and its Standards

• Open Geospatial Consortium (OGC)– non-profit, international, voluntary consensus standards

organization that is leading the development of standards for geospatial and location based services.

• OGC Web Coverage Service (WCS)– Web service for actual geospatial coverage data access

• OGC Web Map Service (WMS)– Web service for geospatial data (coverage or feature)

visualization• Goal: interoperability

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The ORNL WCS and WMS Servers

• MapServer-based• WCS

– http://webmap.ornl.gov/ogcbroker/wcs?– Version 1.0.0– Customized geospatial coverage access

• Spatial/temporal/band subsetting• Reprojection/resampling• Reformatting: GeoTIFF, Arc/Info ASCII Grid, netCDF, NITF, and ERDAS Imagine

• WMS– http://webmap.ornl.gov/ogcbroker/wms?– Version 1.1.1– Customized geospatial data visualization

• Automatic/manual-defined color scheme• Spatial/temporal/band subsetting• Reprojection/resampling• Popular image formats: PNG, JPEG, and GIF

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Spatial Data Access Tool (SDAT)

• http://webmap.ornl.gov/wcsdown• OGC standards-based Web application for

geospatial data visualization and download• Web-based GUI brings the benefits of ORNL

WCS/WMS servers to end users– interactive map widget – driven by WMS– customized data download – driven by WCS

• Two levels of data organization– Data set– Data file (granule)

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65 Data Sets in SDAT

• Land Cover – 6– MODIS, AVHRR, GLC2000, NLCD 2001, etc.

• Elevation – 2– GTOPO30, SRTM

• Soil – 4• Climate – 5

– Koppen-Geiger climate classification• Ecoregion – 1• Carbon cycling model outputs – 30

– ORCHIDEE, SiB3, CLM-CASA, etc.

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SDAT User Interface – Set Level

• Browse data sets/files• Link to detailed metadata in data set level

data set list data file (granule) list

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SDAT User Interface – File Level

• file-level metadata• projection definition in

OGC WKT format• OpenLayers-based

interactive map widget• On the fly map

reprojection• WCS-based data access

options

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Virtual Globe technology

• World-Wide Web– SDAT is Web-based

• Web-Wide World– Emerging “virtual globe” technology, like Google

Earth, brings a new platform and many more benefits for geospatial data visualization and delivery

Local Computer

World-Wide Web (SDAT)

Web-Wide World (Google Earth)

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Google Earth KMZ

• A KMZ file for each data set is provided for users to visualize data in Google Earth

– thanks to Karl Benedict and Renzo Sanchez-Silva for the ESIP-EDAC WMS to KML converter

• WMS-based dynamic maps generation• WMS-based dynamic legend images

generation

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Benefits (1)

• Rich and valuable background maps (high resolution satellite images, roads, landmarks, borders, etc.)

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Benefits (2)

• Powerful address/keywords-based locating capability

– what if the user want to see a data near Yosemite?

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Benefits (3)

• Excellent data visualization capability

Google Earth wraps National Land Cover Data (NLCD 2001) to terrain

– globe-based– arbitrary angle

of view– fly– 3-D– terrain

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Benefits (4)

• Overlay any map from any data set– Land cover change in Three Gorges Dam area

MODIS Land Cover (IGBP) in 2001MODIS Land Cover (IGBP) in 2007What we see• Increase of water area

• Reduce of croplands

• Woody Savannas replaced by Mixed Forests

What we think• Impact on environment

• residency relocation

• more …

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Benefits (5)

• Time-series animation– Monthly CO2 flux for the period 1998 – 2006 at 1 degree

spatial resolution (simulated by SiB3 model)

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Benefits (6)

• Embed SDAT tool within Google Earth– support of Javascript and iframe since version 5

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Summary and future work

• ORNL DAAC and MAST-DC are rich sources for biogeochemical and ecological data useful in environmental research.

• The ORNL OGC servers and SDAT provide efficient and customizable visualization and access to geospatial data in a standard way

• Google Earth serves as a new platform and brings many more benefits for geospatial data visualization and delivery

• Incorporate more OGC standards, such as WFS

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Thank you!

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Client Software

Role of SDAT

SDAT

OGC Servers(WCS/WMS/…)

Metadata Catalog

(Mercury)

Data Order System

User

Metadata Archive

Data Center (ORNL DAAC, MAST-DC, ..)

Data Archive