The Digital Chart of the World (DCW) is an Environmental Systems
Research Institute, Inc. (ESRI) product originally developed for the US
Defense Mapping Agency (DMA) using DMA data. The DCW 1993 version at
1:1,000,000 scale was used. The DMA data sources are aeronautical
charts, which emphasize landmarks important from flying altitudes. This
explains why there is a separate aeronautical theme with all conceivable
airports, yet why on some themes small islands and lakes are simply
unnamed points. ESRI, in compiling the DCW, also eliminated some detail
and made some assumptions for handling tiny polygons and edgematching.
Also, note that the completeness of the thematic categories present in
each layer will vary. Please read the layer descriptions (through links
in the following table).