39 Shapefile format

Shapefile is a geospatial vector data format for geographic information systems (GIS). It was developed and is regulated by the Esri Company. It is considered an open format, though it is proprietary. Since it is open, the format is supported by many free and open-source map processing applications. Shapefile can spatially describe vector features (points, lines and polygons of rivers, lakes and wells, for example), and each item usually has attributes that describe it, such as name and temperature.

Despite having a singular name, the shapefile format consists of a collection of files with a common filename and different extensions stored in the same directory. The following three files are mandatory for a shapefile to work properly: .shp, .shx and .dbf. The actual shapefile is the .shp file, but if distributed alone, it will not be able to display the stored data. The distribution must be done together with the other two files.

Required files are the following:

● .shp - shape format; the feature geometry itself

● .shx - shape index format; an index with the geometry's features to allow faster searches

● dbf - attribute format; columnar attributes for each "shape"

In each of the required files, the shapes in each file correspond to each other in sequence (the first record in the .shp file corresponds to the first record in the .shx and .dbf files, and so on).

It is not feasible to generate shapefiles manually, as would be possible to create CSV, XML and JSON files, because they are binary. Typically, these files are created from manipulating points and features on maps in its own GIS software.