I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. Document editors and WG chairs should treat these comments just like any other last call comments. This document specifies an extension to the Presence Information Data Format Location Object (PIDF-LO, RFC 4119) so that location information can be given relative to a base point. It is pretty general, allowing the relative location to be various shapes or specified with a map. Both XML and TLV representations are provided. The Security Considerations section seems reasonable to me for a data format specification document. It refers to the base RFC 4119 specification be also briefly touches on a covert channel that the representation would otherwise have made available in some cases. I feel comfortable with the existing Security Considerations section. Thanks, Donald ============================= Donald E. Eastlake 3rd +1-508-333-2270 (cell) 155 Beaver Street, Milford, MA 01757 USA d3e3e3 at gmail.com