Geocatalogue of geospatial information resources discovered on Google

T. Kliment1, M. Kliment2, V. Cetl3

1Slovak University of Technology, Faculty of Civil Engineering, Bratislava, Slovakia

2Slovak University of Agriculture, Horticulture and Landscape Engineering Faculty, Nitra, Slovakia

3University of Zagreb, Faculty of Geodesy, Zagreb, Croatia

Nowadays many ways exist to search and retrieve geospatial information (GI) on the web. Very well know and mostly used systems for spatial browsing such as Google Maps provide an easy and user friendly way to discover daily used GI as for instance addresses, points of interest and routes between them, etc. On the other hand Spatial Data Infrastructure (SDI) provides more detailed information (on protected sites, natural hazard risk zones, energy resources, geology, etc.) with advanced level of searching possibilities based on their documentation through metadata. However, data provider needs to create and publish metadata in a predefined structure describing her/his GI resources in order to make them discoverable through SDI. This fact may decrease the amount of GI resources available through current geoportals on a global (e.g. GEO Portal[1]), Regional (INSPIRE Geoportal[2]) or National level (Geoportal SR[3]). Furthermore, as current research activities have reported, so called mainstream web provide many valuable GI resources of several types (e.g. OGC Services, KML data, etc.) to be discovered using internet search engines such as Google, Yahoo or Bing. The benefit of search engines is that they are crawling the web to discover information resources automatically. Therefore no additional work is required, besides to publish URL addresses of available resources on a web page or portal.

The work describes the Geocatalogue of geospatial information provided by OGC services discovered on Google (Fig.1), which has been implemented as a result of a methodology proposed to discover OGC services on the mainstream search engine Google. The GetCapabilities URL addresses were searched for 7 types (WMS, WFS, WCS, WPS, SOS, WMTS and CSW) of OGC services. The URL addresses of discovered OGC services were stored in database and verified to define their availability and retrieve service versions. Metadata harvesting tasks were created and run for functioning services in GeoNetwork opensource in order to collect metadata for both services and the GI resources they provide (WMS Layers, WFS Features, WCS Coverages and SOS Observations).

Figure 1 Geocatalogue of geospatial information provided by OGC services discovered on Google.

Collected metadata are available to be used for searching, evaluation and use of GI resources discovered on Google through geocatalogue on URL: http://tokenbros.com:8082 or through INSPIRE discovery services provided for entire catalogue[4] content, or for each GI resource type (WMS services[5], WMS Layers[6], WFS Services[7], WFS Features[8], etc.).

The described work may contribute to current SDI implementation with such GI resources that are not provided through available geoportals due to non-existence of required metadata (e.g. ISO/INSPIRE), nevertheless are still available on the web.

[1] http://www.geoportal.org

[2] http://inspire-geoportal.ec.europa.eu/

[3] http://geoportal.sazp.sk

[4] http://tokenbros.com:8082/geonetwork/srv/eng/csw

[5] http://tokenbros.com:8082/geonetwork/srv/eng/csw-wms

[6] http://tokenbros.com:8082/geonetwork/srv/eng/csw-wms-layers

[7] http://tokenbros.com:8082/geonetwork/srv/eng/csw-wfs

[8] http://tokenbros.com:8082/geonetwork/srv/eng/csw-wfs-features