shapefiles

Shapefiles are a widely used geospatial vector data format for geographic information system software. They store geometric features such as points, lines, and polygons along with associated attribute data, enabling mapping and spatial analysis across diverse applications. A shapefile is not a single file; it is a set of related files that must be kept together.

The core components are at least three mandatory files: the .shp file, which contains geometry; the .shx index file, which links shapes to their records; and the .dbf attribute file, which stores tabular attributes in dBASE format. Optional files include the .prj file with a human-readable coordinate reference system definition (WKT), the .cpg file specifying character encoding for the DBF, and optional spatial index files such as .sbn and .sbx. In practice, a complete shapefile dataset consists of all relevant files with the same base name.

Shapefiles support 2D geometry with optional Z and M dimensions and can represent null geometries. They allow multiple parts within a single feature, enabling multipart polygons or polylines. Each feature’s attributes correspond to the records in the associated DBF file.

Developed by Esri in the 1990s, the Shapefile specification was released publicly and became a de facto standard for vector GIS data exchange. Despite broad compatibility and tooling, shapefiles have limitations, including lack of inherent topology, a recommended 2 GB size limit, and limited support for advanced schema or complex geometries. Today, shapefiles remain common for data sharing and legacy workflows, though newer formats like GeoPackage and GeoJSON increasingly complement or replace them for long-term storage and interoperability.