Spatial search engines are specialized search engines primarily dedicated to retrieve geographical information through web technology. They provide capabilities to query metadata records for related spatial data, and link directly to the online content of spatial data themselves. OpenSearch-Geo extensions are developed to facilitate basic geographical data search using Open-search method. OpenSearch-Geo extensions add new parameters of geographic filtering for querying spatial data and recommended set of simple standards responses in geographic format, such as KML, Atom and GeoRSS though spatial search engines. The communication method used in spatial search engines is based on standardized-service-oriented-architecture.