Data Format B-7 GIS Shapefile

The Shapefile format stores nontopological geometry and attribute information for spatial features in a data set. A Shapefile consists minimally of the main file, an index file, and a dBASE table.

In the main file, the geometry for a feature is stored as a shape comprising a set of vector coordinates. This main file is direct access, variable-record-length file in which each record describes a shape with a list of its vertices. In the index file, each record contains the offset of the corresponding main file record from the beginning of the main file. Attributes are held in a dBASE format file. The dBASE table contains feature attributes with one record per feature. Attribute records in the dBASE file must be in the same order as records in the main file. Each attribute record has a one-to-one relationship with the associated shape record.

Example:

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