Hydrographic Data Codes
IHO 23-4th: Limits of Oceans and Seas, Special Publication 23, Draft 4th Edition 1986, published by the International Hydrographic Bureau of the International Hydrographic Organization.
IHO 23-3rd: Limits of Oceans and Seas, Special Publication 23, 3rd Edition 1953, published by the International Hydrographic Organization.
ACIC M 49-1: Chart of Limits of Seas and Oceans, revised January 1958, published by the Aeronautical Chart and Information Center (ACIC), United States Air Force.
DIAM 65-18: Geopolitical Data Elements and Related Features, Data Standard No. 4, Defense Intelligence Agency Manual 65-18, December 1994, published by the Defense Intelligence Agency.
The US Government has not yet adopted a standard for hydrographic codes. The names and limits of the following oceans and seas are not always directly comparable because of differences in the customers, needs, and requirements of the individual organizations. Even the number of principal water bodies varies from organization to organization. The recently delimited Southern Ocean is not included.
| Body of Water | IHO 23-4th | IHO 23-3rd | ACIC M 49-1 | DIAM 65-18 |
|---|---|---|---|---|
| Arctic Ocean | 9 | 17 | A | 5A |
| Atlantic Ocean | - | - | - | - |
| Baltic Sea | 2 | 1 | B26 | 7B |
| Eastern Mediterranean | 3.1.2 | 28 B | - | 8E |
| Indian Ocean | 5 | 45 | F | 6A |
| Mediterranean Sea | 3.1 | 28 | B11 | - |
| North Atlantic Ocean | 1 | 23 | B | 1A |
| North Pacific Ocean | 7 | 57 | D | 3A |
| Pacific Ocean | - | - | - | - |
| South Atlantic Ocean | 4 | 32 | C | 2A |
| South China and Eastern Archipelagic Seas | 6 | 49, 48 | D18 plus others | 3U plus others |
| South Pacific Ocean | 8 | 61 | E | 4A |
| Western Mediterranean | 3.1.1 | 28 A | - | 8W |