An HDFEOS Data Server Based on OPe NDAP
An HDF-EOS Data Server Based on OPe. NDAP and ECHO Bob Bane, Mohammad Rabi, Weijun Su, Richard Ullman, Jingli Yang, Zhangshi Yin Data Usability Group, NASA/GSFC
HDF-EOS data access via web • Findable – With standard search engines – With domain-specific engines • Browseable – Per-granule web page • Readable metadata • Links for fetching data • Retrievable – – Whole dataset Metadata only Individual fields Sectorized fields
Intended Audience • Groups that are generating HDF-EOS products • Need a straightforward, inexpensive way to publish them to the web • Major archives already have their own systems - this is for everyone else
Tools used • Standard tools – Unix shell scripts – Apache web server • Earth science standards and protocols – OPe. NDAP – ECHO • Our tools – ODL <-> XML <-> HTML
OPe. NDAP • “net. CDF via HTTP” • Also works for HDF 4/5 and HDF-EOS 2/5 • http: //opendap. org
ECHO • EOS Clearing. House • Searchable repository for earth science metadata • Based on standard commercial tools – Databases – E-commerce middleware • http: //echo. eos. nasa. gov
Our Tools • hemu - extracts ODL metadata • odl 2 xml - converts ODL to EOS-compatible XML • heex - breaks an HDF-EOS dataset into field files with an HTML/XML table of contents • XSLT stylesheets - convert XML to pretty HTML
OPe. NDAP server HDF_EOS files hemu Fetch/sectorize heex DODS client ODL metadata odl 2 xml XML contents Field files Web server Browse/fetch Web browser ECHO client XML metadata XSLT Pretty HTML XSLT ECHO XML Implemented by us Search engines ECHO server Other tools Search/query File transfer Web/HTTP Client-side services
Installation • Foundation – Unix – Apache – Java • Libraries – HDF 4/5, HDF-EOS 2/5 – SDP Toolkit – OPe. NDAP server • Our software – heex, odl 2 xml, hemu – heserve scripts
Use • Two shell scripts – ingest granule-file. hdf • Publishes granule to the web – echoingest metadata. xml • Publishes web links for granule to ECHO • Optionally called by ingest
Granule Web Pages
Granule Web Pages
Granule Web Pages
Granule Web Pages
Screen shot Showing link dragged into DODS client
Where is the software? http: //hdfeos. gsfc. nasa. gov ’Tools’ link heserve system
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