| Attribute type: A | Used in: |
| country (c2): | Two letter code according to ISO 3166 (refer to Annex A to S-57 Appendix A) | |
| authority (c2): | A string of two alphanumeric characters (refer to Annex A to S-57 Appendix A), e.g. German Bundesamt für Seeschiffahrt und Hydrographie = DE; US National Imagery and Mapping Agency = U1. | |
| procedure (c4): | digitized = digi scanned = scan alpha/numeric input = alph |