Geodata Discovery Working Group

This is a Working Group started by the Public Geospatial Data Committee.

NOTICE: There are two BOFs on this topic at FOSS4G2006 on Geodata and about Geodata Discovery and Metadata Models.

While OSGeo can consider hosting sets of public geodata, (and for the purposes of offering maintained packages of high-quality data for education and demonstration, it probably will), we can compile a set of best practises and references to good prior art for building and maintaining collections of data and metadata.

Focus

Metadata for collections of geographic information.
Providing best practise and prototypes for geodata search facilities
Help with providing input into the OSGeo repository/services at http://osgeo.telascience.org/
Providing 'catalog'/discovery/search services as part of OSGeo activities in promoting access to public domain and open licensed bodies of data.

Participants

Existing (Meta) Search Projects and Related Efforts

More on metadata models at Geodata_Metadata_Requirements

Search services:

See Geodata_Metadata_Requirements#Discovery
(Meta) Data Catalogues / Data Repositories
- GeoTorrent hosts BitTorrents of shapefile/TIFF format data.
- GeoNetwork "Find Interactive Maps, GIS datasets, Satellite Imagery and Related Applications"
- DLESE Collection System offers a metadata repository and editor and supports OAI-PMH as data provider and harvester
- Geo Meta Data Base (GMDB) - Metadata repository and editor based on ISO 19115/119 Metadata and Dublin Core with XML export and OAI-PMH data provider support (german only)
- GDI Portals (country specific): US, UK, D, A, CH, LI, FR, CO...
(Meta) Search engines:
- geometa.info - search engine for geospatial services, data and documents combining structured and unstructured data (currently german only)
- Google search using 'allinurl' parameter
- The Mapdex global Index has been discontinued.

Lists about data sources and services:

Lists on web services:
- http://www.skylab-mobilesystems.com/ger/wms_serverlist.html simple WMS service URL list
- http://www.refractions.net/white_papers/ogcsurvey/ Automated OGC Survey on the Web (WMF, WFS, ...)
- http://geometa.info/search.jsp?query=type%3Awms WMS search engine
- http://exploreourpla.net/maps/
- http://wms-sites.com/ catalog of WMS sites
- Orthophotography Annotated list of Orthophotography WMS Services
Lists on data services:
- http://datagateway.nrcs.usda.gov/ US data servers

Public Datasets for Possible Mirroring or Distribution

Regional data sets

These data sets comprise raster and vector data (with permittive license):

Gazetteer Data

... basically placenames with coordinates ...

Geonames.org gazetteer (includes NGA GNS Gazetteer)
WorldWind Placenames (markusN can provide PERL to read this)
Geowanking-List: Toponymic accurracy of Google and Yahoo Maps => a very good example why releasing this data is useful for public authorities and the society

Vector data

VMAP0 - 1:1Mio, very generalised vector data for many features, around 70 layers (already at telascience) - see also here for docs
World map for APRS, 1:1.1mio
GSHHS - world coastlines, different scales available
TIGER/Line (USA) - street and addressing data for the US
RNF (Canada) - street and addressing data for Canada
OpenStreetMap - data available through a HTTP based XML interface. They've also been getting requests for shapefile and GML output of their data.
African geodata

Raster data

DEM
- SRTM V2
- ETOPO2
- TOPEX: SRTM30 (with GTOPO30 data for high latitudes where SRTM data are not available)
- NOAA TCM LIDAR / IfSAR
Satellite Data
- Landsat (OnEarth - mirror already at telascience)
- Blue Marble / Blue Marble Next Generation (mirror already at telascience)
- ASTER (from GLCF)
- MODIS (from NASA EDC)
- USGS Urban Orthos (URL?)
Maps derived from Satellite Data
- Nested Imagery Layer (Best of -- resolution -- with seamless zoom through multiple levels)
- AVHRR Landuse Map from GLCF
- natural earth
- City lights
- HydroSHEDS - Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales
- UNOSAT imagery http://unosat.web.cern.ch/unosat/asp/prod_free.asp

Wishlist for Public Datasets

Orthophotos
- Possible sources:
- http://www.fgdl.org/download/index.html
- http://datagateway.nrcs.usda.gov/

Search Protocols

GIS-specific:
- OGC's CSW 2.0 (work in progress...)
  - OpenGIS Catalogue Services - ebRIM (ISO/TS 15000-3) profile of CSW
  - (ISO/OGC's "ISO19115/ISO19119 Application Profile for CSW 2.0")
  - See a comparison between CSW and OAI-PMH
- OGC's WFS (profile) serving (profiled) ISO 19115/19119 metadata format...?
- 'Lean and mean' proposals on project level...
  - Simple Catalog Interface
Related search/harvest protocols - possibly to be profiled or specialized by geoinformation requirements:
- OAI-PMH (Open Archives Initiative Protocol for Metadata Harvesting 2.0)
  - See also mod_oai, an Apache module under development
- Search/Retrieve via URL (SRU/SRW)
- OpenSearch proposal from A9
- Z39.50 ANSI/NISO standard protocol
- ebXML/ebRIM Messaging Service 2.0

Hosting Plan

(placeholder for an initial hosting plan sketch)