Digital Chart of the World
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The Digital Chart of the World (DCW) is a comprehensive digital map of the world. It represents the most comprehensive GIS global database that is freely available as of 2006, although it has not been updated since 1992.
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[edit] Origin of the Digital Chart of the World
The primary source for this database is the U.S. Defense Mapping Agency's (DMA) Operational Navigation Chart (ONC) 1:1,000,000 scale paper map series produced by the United States, Australia, Canada, and the United Kingdom. These charts were designed to meet the needs of pilots and air crews in medium-and low-altitude en route navigation and to support military operational planning, intelligence briefings, and other needs.
[edit] Data structure
The database is divided into 2,094 tiles that represent 5-degree by 5-degree areas of the globe, although if the data set is obtained from Penn State the data is broken up by pre-1992 national boundaries, whilst NIMA distributes the data set in just five tiles. The data currency varies from place to place, ranging from the mid 1960s to the early 1990s.
Digital Chart of the World thematic layers are:
- Political/Ocean (country boundaries)
- Populated Places (urbanized areas and points)
- Roads
- Railroads
- Aeronautical Structures
- Utilities (electrical, telephone, pipelines)
- Drainage System
- Hypsographic data
- Land Cover
- Ocean Features
- Physiography
- Cultural Landmarks
- Transportation Structure
- Vegetation
- Data Location
[edit] See also
- Vector Map (VMAP0 and VMAP1 data)
- Digital elevation model
- Digital terrain model
