**Table of Contents**

The `nomenclature.xls`

is the main file composing the description of a nomenclature.
It details all the information needed to integrate the nomenclature into the Library.

This file must have a strict structure defined in the present section.

The entire spreadsheet must be divided into several sheets according to the following rule:

Each sheet must have the title corresponding to its contents and defined in the Table 2.1. For example, the list of statistical units composing a nomenclature must be put in the sheet called "

`units`

".Each sheet can contain no more than 65536 rows (limitation of the Excel format). If their effective number is greater, the entries must be divided between several sheets. Each name of the sheet, chosen according to the previous rule, must be completed with a numeric index of the sheet corresponding to the ordinal of the part of the items it describes. For example, a nomenclature composed of 80000 units will have the following sheets:

`units1`

and`units2`

, where the first one will contain 65536 units and the second the remaining part of 14464 units.

The spreadsheet of `nomenclature.xls`

file can contain the following sheets:

**Table 2.1. nomenclature.xls file structure**

Sheet name | Obligation | Description |

`about` | Mandatory | Contains general information about the package and its originator. |

`version` | Mandatory | Contains general details on the nomenclature described. |

`units` | Mandatory | Identifies the statistical units composing the nomenclature. |

`names` | Mandatory | Lists the names of the statistical units. |

`hierarchy` | Mandatory for hierarchical nomenclatures. Meaningless for non-hierarchical ones. | Establishes hierarchical relations between the units of the nomenclature. |

`changes` | Mandatory for new versions of supported nomenclatures. Meaningless for new (original) nomenclatures. | Lists the changes that characterize the described version of the nomenclature as compared with the previous one. |

`derivations` | Optional for derived nomenclatures. Meaningless for original ones. | Provides the information about the relationship between the units of a derived nomenclature and the ones of the original one. |

`equivalence` | Optional | Establishes relationship between the units of the described nomenclature and other supported nomenclatures. |

`study_area` | Optional | Establishes relationship between the units code and the country it belongs to. Aims at associating the units codes with a study area for the "where" filter of the ESPON Database Portal Search Query. |

The names of the sheets are not case sensitive.

The following sections give detailed descriptions of the contents of these sheets.