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Creation of a Comprehensive Managed Areas Spatial Database for the Conterminous United States (96-4)

  • McGhie, R. Gavin
Publication Date
May 01, 1996
eScholarship - University of California
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In this report, the creation of a digital, spatially referenced database of managed areas in the conterminous United States is described. A Geographic Information System (GIS) was used for database compilation to provide a high degree of flexibility for updates, queries, and manipulations. As concern over the degradation of ecosystems increases, so does the need for information about the spatial location and aerial extent of managed and protected areas. Recently, focus on the ecological issues of environmental preservation has been shifting from protection of individual endangered or sensitive species to protection of entire interrelated ecosystems. To meet the demands of studies in this area, datasets for large areas of land must be created and/or compiled. Guidelines and methods for creating these types of large datasets must also be established; currently there is little information of this type available. These factors were the motivation for the creation of this Managed Areas Database (MAD). This database contains all types of managed areas existing in the conterminous United States, including land held by federal, state, tribal, and private agencies and organizations. This large number of public agencies with land holdings and the numerous area designations makes the task of gathering and integrating managed areas data difficult and time consuming. MAD was developed at an approximate map scale of 1:2,000,000, with a Minimum Mapping Unit (MMU) of about 100 hectares. A number of digital and hard copy map sources were employed in compilation of this database. The database is divided into two separate GIS coverages. The first is a data layer containing polygons showing the boundaries of managed areas. The second is a layer containing data points which represent managed areas that are not large enough to meet the MMU requirements for the polygon coverage. Point coverage data may be less useful in some studies, however, it was felt that including all managed areas from the available map sources would produce a more complete database. This technical summary document describes both the methodology employed and problems encountered in creating this managed areas database. In this document, we describe attributes available in the database, map sources used for compilation, classification of managed areas, integration of map sources, and possible sources of error. This managed areas GIS database can be combined with other information layers such as species and ecosystem distribution to allow comparison of administrative and ecological boundaries which may or may not coincide. Researchers will also be able to begin assessing the degree of protection given certain species or ecosystems at regional or national scales, and this database may someday be part of a much needed global coverage of managed areas.

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