This document defines an extension to PIDF-LO (RFC4119) for the expression of location information that is defined relative to a reference point. The reference point may be expressed as a geodetic or civic location, and the relative offset may be one of several shapes. An alternative binary representation is described. Optionally, a reference to a secondary document (such as a map image) can be included, along with the relationship of the map coordinate system to the reference/offset coordinate system to allow display of the map with the reference point and the relative offset.