Shapefiles were invented by ESRI (Earth Systems Research Institute) in the early 1990s, and have become widely used as a type of vector GIS data, especially in the open source world. A shapefile is in reality a collection of at least three separate files, all with the same root name but different file extensions (.shp, .shx, .dbf, .prj), which combine to describe vector (points, lines, and polygons) features of interest. Special GIS software can read these as one “shapefile”.