Geoportals provide a single point of access for searching for and downloading GIS data from a multitude of sources. Users looking for GIS data can search a variety of geoportals for government and open GIS data. President Clinton signed an executive order in 1994 mandating the establishment of a federal spatial data infrastructure depository (Budhathoki, Bruce, & Nedovic-Budic, 2008). The resulting United States National Spatial Data Infrastructure (NSDI) is considered the first geoportal concept. Since then, hundreds of geoportals have been established by government agencies such as data.gov for downloading open data from the United States government, commercial GIS companies such as Esri recently launched ArcGIS Open Data effort, and universities. . Tufts, Harvard, and MIT have spearheaded the development of OpenGeoportal.org, which is self-described as an “open source, federated web application to rapidly discover, preview, and retrieve geospatial data” and universities that are applying this software include UC Berkeley Geospatial Data Repository, Harvard Geospatial Library, and GeoData@Tufts.
A list of multi-organizational and national geoportals:
ArcGIS Online (Global)
INSPIRE (Europe)
GEOSS (Global Earth Observation Data)
Land Information New Zealand Data Service (New Zealand)
Geoportal Patrimonio Natural y de la Biodiversidad del Estado español (Spain)
Geoportal Spain is Culture (Spain)
Geoportal Pueblos Arquitectura Negra Guadalajara (Spain)
Geoportal hotelmapspain-madrid (Spain)
Geoportal Campiña de Jerez (Spain)
Geoportal Madrid (Spain)
IDE Andorra (Andorra)
Geoportal de Chile (Chile)
Geoportal del Departamento Nacional de Estadística Colombia (Colombia)
Geoportal (Croatia)
Geodata-info (Denmark)
Geoportal (Finland)
Geoportail (France)
GeoVisitGuatemala (Guatemala)
India NSDI Portal (India)
Portale Cartografico Nazionale (Italy)
Geoportal (Lithuania)
Geoportal (Luxembourg)
PDOK (Netherlands)
UNSDI Netherlands GeoNetwork portal (Netherlands)
Geospatial Data Service Centre (Netherlands)
GeoNorge (Norway)
Geoportal (Poland)
SNIG (Portugal)
Geoportal of RosKosmos (Russian Federation)
NSDI of Russian Federation (RU)
Geoportal (Serbia)
IDEE (Spain)
Geoportal Bund (Switzerland)
UK GeoPortal (UK)
GoGeo (UK)
Data.gov (USA)
Geospatial Platform (USA)
NSDI Clearinghouse Network (USA)
Geoportal Simón Bolívar (Venezuela)
source :
http://www.gislounge.com/geoportals/