No abstract

Humans have always exchanged geographic information, but the practice has grown exponentially in recent years with the popularization of the Internet and the Web, and with the growth of geographic information technologies. The arguments for sharing include scale economies in production and the desire to avoid duplication. The history of sharing can be viewed in a three-phase conceptual framework, from an early disorganized phase, through one centered on national governments as the primary suppliers of geographic information, to the contemporary somewhat chaotic network of producers and consumers. Recently geolibraries and geoportals have emerged as mechanisms to support searches for geographic information relevant to specific needs. We review the design of the Geospatial One-Stop (GOS), a project sponsored by the U.S. Federal Government to provide a single portal to geographic information, and reflecting the current state of the art. Its design includes a portal to distributed assets, accessible through a simple Web browser, a catalog based on the widely used Federal Geographic Data Committee metadata standard, services to assess and validate potential accessions, directories to available geographic information services, and automated metadata harvesting from registered sites. GOS rep resents a significant technological advance, however, its potential to provide a general marketplace for geographic information beyond government data has not been realized. Its future will be driven in part by technological advances in areas such as searching and automated metadata harvesting, as well as by clearer definition of its domain, either as the geoportal for U.S. data or as a broader geoportal with appropriate international or private partners. Incorporation of informal and heuristic search methods used by humans appears to offer the best direction for improvement in search technologies.

Land-use history, recent management, and landscape position influence vegetation at the Rockefeller Experimental Tract (RET), a 40-year-old restoration experiment in northeast Kansas. RET is representative of the prairie-forest ecotone, containing native tallgrass prairie and oak-hickory forest, but unique in having tracts of replanted prairie, seeded in 1957, that have undergone long-term restoration treatments: burned, grazed, mowed, or untreated. A land-use history database for RET was compiled using a geographic information system to integrate historic and contemporary sources of information. Restoration management on the reseeded prairie has had a profound effect on forest development: mowing or burning precluded forest establishment (<3% forest cover), whereas portions of untreated or grazed areas became heavily forested (>97% forest cover). Forest colonization depends upon biotic and edaphic conditions at the time restoration was initiated: for areas replanted to prairie and managed by grazing, forestation was 6% on land in cultivation prior to replanting, 20% on former pastureland, and 98% on land deforested just before replanting. Patterns of forest colonization were also significantly associated with three landscape positions: near existing forest, along water courses, and along ridge

No abstract

Along with a rapid growth in the volume of user-generated video clips, efficient video retrieval methods have become one of the most critical challenges in multimedia management. In this article, we propose a service framework using geographic information for retrieval of the videos on the web. The main idea is to describe and query videos by video-related geographic data such as video location, field of view and trajectory. Based on the point, line and polygon description for videos, we define the commonly used video retrieval methods. A video retrieval service framework and the service interfaces are designed based on the REST architecture. A prototype system is also implemented to test the services. The experiment shows that the proposed video description, retrieval methods and web services are feasible and useful. We believe that the integration of geographical video retrieval methods into existing methods will promote the geo-tagged video sharing, discovery and consumption in various web applications.