The top-level data structure for an EDIGéO dataset is the exchange. An exchange appears as a single .THF file. This file does not hold the main data; instead it specifies which lots belong to the exchange. An exchange, therefore, consists of one or more lots.
A lot in EDIGéO is conceptually a dataset. Within a lot, all data is self-contained. Therefore, opening an exchange file with multiple lots is conceptually identical to opening several exchange files each having one lot.
An EDIGéO lot is described in several plain text files. These files are listed below:
|
Extension |
Cardinality (per lot) |
Description |
|
.GEN |
one |
General information |
|
.GEO |
one |
Geographical information |
|
.QAL |
zero or one |
.QAL files hold quality information. Quality data may describe information about the source of the data, or its up-to-dateness. |
|
.DIC |
zero or one |
.DIC files hold nomenclature data, such that EDIGéO objects, attributes, and relationship entities can be matched with a standardized nomenclature scheme. |
|
.SCD |
zero or one |
.SCD files holds schema information. This file holds conceptual model information for attributes, relationships, and topological data entities. (This information is used to generate feature types in FME.) |
|
.VEC |
one to N |
.VEC files holds vector data. Each .VEC file describes an EDIGéO subset. Multiple subsets can share the same schema, quality, and nomenclature data. Data in .VEC files comes in five forms: node, edge, face, link, and feature primitives. These primitives form the building blocks for the topological features. |