diff --git a/GENERAL.md b/GENERAL.md
index 96da418..424cf90 100644
--- a/GENERAL.md
+++ b/GENERAL.md
@@ -11,6 +11,7 @@ Data are stored in property files. Each entry line uses key defined by conventio
 | DATE | A date in ISO format | ISO_DATE  | 2020-07-06 |
 | DATETIME | A date and time in ISO format | ISO_DATETIME  | 2020-07-06T14:23:20 |
 | DAYS | List of 366 NUMERIC separated by SEPARATOR | STU | 1;2;3;4;5;…;365 |
+| DECIMAL_DEGREE | Longitude or latitidue value | ^[+-]?\\d+[,\\.]\\d{1,8}$ | -12,3456 |
 | EMAIL | An electronic address. | ^.+@.+$ | christian@momon.org |
 | MONTHS | List of 12 NUMERIC separated by SEPARATOR | STU | 1;2;3;4;5;6;7;9;10;11;12 |
 | NUMERIC | A numeric value | STU | -1234.567 |