# ILCD Format 1.1 Documentation - Data Types

Data Type | Base Type | Description
--- | --- | ---
CASNumber | xs:string | CAS Number, leading zeros are requried.
FT | xs:string | Free text with an unlimited length.
FTMultiLang | FT | Multi-lang free text with an unlimited length.
@xml:lang |  |
GIS | xs:string | Global geographical reference in Latitude and LongitudeExamples: "+42.42;-180", "0;0", "13.22 ; -3
GlobalReferenceType |  | Represents a reference to another dataset or file. Either refObjectId and version, or uri, or both have to be specified.
@type | GlobalReferenceTypeValues | (required) - indicates the type of the referenced dataset/file. One of GlobalReferenceTypeValues.
@refObjectId | UUID | UUID of the referenced object
@version | Version | version number of the referenced object
@uri | xs:anyURI | URI of the referenced object
subReference | String | Valid only for references of type "source data set". Allows to make references to sections, pages etc. within a source.
shortDescription | STMultiLang | Short, clear-text summary of the referenced object that can be used as a hint what to expect behind the reference in cases where it cannot be resolved.
other |  |
Int1 | xs:integer | 1-digit integer number
Int5 | xs:integer | 5-digit integer number
Int6 | xs:integer | 6-digit integer number
LevelType | Int1 | 1-digit integer number, must be equal to or greater than 0
MatR | xs:string | Mathematical rule
MatV | xs:string | Mathematical variable or parameter
NullableString | xs:string | String with a maximum length of 500 characters. May be empty.
Perc | xs:decimal | percentage amount
Real | xs:double | 38-digit real number
ST | xs:string | Short text with a maximum length of 1000 characters.
STMultiLang | ST | Multi-lang short text with a maximum length of 1000 characters.
@xml:lang |  |
SchemaVersion | xs:string | Version number
String | xs:string | String with a maximum length of 500 characters. Must have a minimum length of 1.
StringMultiLang | String | Multi-lang string with a maximum length of 500 characters.
@xml:lang |  |
UUID | xs:string | Unique Universal Identifier, 16-byte hex number
Version | xs:string | Version number
Year | xs:integer | 4-digit year
boolean | xs:boolean | true, false, 1, or 0
dateTime | xs:dateTime | Date and time format acc. to ISO 8601, chapter 5.4