Length of Coastline

The measurement of an irregular and curving feature such as a nation's coastal length is scale-dependent and very difficult to measure. Maps of individual islands for example, frequently show great detail, whereas regional maps summarize complex coastlines into a few simple lines. In addition, coastal features are constantly changing due to erosion, etc. The only way to derive comparable statistics on coastline length is to use a single source which uses a constant scale. This is what has been attempted with the data presented in this table, however, highly complex coastlines will appear longer at higher resolutions. Estimates may differ from other published sources.

Because of the difficulty in trying to measure coastline length, these figures should be interpreted as approximations and should be used with caution. Coastline length was derived from the World Vector Shoreline database at 1:250,000 kilometers. The estimates presented here were calculated using a Geographic Information System (GIS) and an underlying database consistent for the entire world. The methodology used to estimate length is based on the following: 1) A country's coastline is made up of individual lines, and an individual line has two or more vertices and/or nodes. 2) The length between two vertices is calculated on the surface of a sphere. 3) The sum of the lengths of the pairs of vertices is aggregated for each individual line, and 4) the sum of the lengths of individual lines was aggregated for a country. In general, the coastline length of islands that are part of a country, but are not overseas territories, are included in the coastline estimate for that country (i.e., Canary Islands are included in Spain). Coastline length for overseas territories and dependencies are listed separately. Disputed areas are not included in country or regional totals.