抄録
The Digital Chart of The World, so-called DCW, is the most frequently used digital global base map. The DCW has 17 layers including seashore lines, national boundaries, land covers, vegetations etc. It was produced by digitizing the Operational Navigation Chart (ONC) with the scale of 1: 1, 000, 000. In this study, the accuracy of the DCW was investigated by comparing it with local maps with the scale of 1: 50, 000 and by comparing with Global Positioning System (GPS) measurements. The maximum errors of about 450 meters in the latitude direction and about 640 meters in the longitude direction were acquired in 27 measured points in Denmark, Japan, Canada, and New Zealand. The result shows that the DCW is not correctly transformed to WGS84. Better digital global base map is required for the purpose of geometric registration of satellite images with 500m or 250m resolution.
