postgis-doc 2.1.8+dfsg-4 (amd64 binary) in ubuntu wily

 PostGIS adds support for geographic objects to the PostgreSQL
 object-relational database. In effect, PostGIS "spatially enables"
 the PostgreSQL server, allowing it to be used as a backend spatial
 database for geographic information systems (GIS), much like ESRI's
 SDE or Oracle's Spatial extension. PostGIS follows the OpenGIS
 "Simple Features Specification for SQL".
 .
 This package contains the PostGIS documentation.