Some data serve many applications and have national extent.
Other data were prepared for a particular time or event, and usually for a limited region. In some cases, similar datasets are also available from some other agency or web site. Our goal is to introduce seamless browse and delivery of the National Elevation Dataset , the National Land Cover Dataset , and the National Hydrography Dataset . The creation of this web site was originally motivated by a need to better manage and maintain project databases that we have used for GIS applications. As we have participated in development of project databases over the last 25 years, we have prepared geospatial data to serve the needs of scientific investigations, land use inventories, natural hazard mitigation, and disaster assessments.