Specification is readily available; supported by other software
Does not support the storage of topological information
Can only store one feature class
It is a collection of 3 or more files:
Required files:
Main file: .shp
This is the primary file that stores feature geometry.
"It's a direct access, variable-record-length file in which each record describes a shape with a list of its vertices." (ESRI)
Stores integer and double-precision numbers (ESRI)
Index file: .shx
Stores the index of the feature geometry.
"Each record contains the offset of the corresponding main file record from the beginning of the main file." (ESRI)
Dbase table: .dbf
Stores the attribute data for features contained in .shp, with one record per feature.
There is a one-to-one relationship between geometry and attributes, which is based on record number. Attribute records in the dBASE file must be in the same order as records in the main file.
It is a mix of binary and ASCII data. Header contains binary data. The records are all in ASCII. (XBase)