What is a .shp file?

The Shapefile is the most widely used format for geographic vector data in GIS (Geographic Information Systems). Despite its name, a "shapefile" is actually a set of at least three files: .shp (geometry), .shx (spatial index), and .dbf (attribute data in dBASE format). Additional sidecar files like .prj (coordinate system), .cpg (encoding), and .sbn/.sbx (spatial index) are common.

The .shp file stores geometry as points, polylines, polygons, or multipoint features, each with coordinates in a defined coordinate reference system. The .dbf file stores attribute data — a table where each row corresponds to a geometric feature. Together, they let you represent anything from census tracts and river networks to building footprints and earthquake epicentres, each with associated data fields.

Shapefiles were introduced by Esri in the early 1990s and became the de facto standard through ubiquity rather than technical superiority. The format has significant limitations: 2 GB file size cap, 10-character field names in .dbf, no support for topology or raster data, and the multi-file design makes them awkward to share. GeoJSON, GeoPackage, and FlatGeobuf are technically superior alternatives, but the Shapefile's installed base is enormous and it remains the default interchange format in government, environmental science, and urban planning.