I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. Document Abstract: This document specifies a Uniform Resource Identifier (URI) for geographic locations using the 'geo' scheme name. A 'geo' URI identifies a physical location in a two- or three-dimensional coordinate reference system in a compact, simple, human-readable, and protocol-independent way. The default coordinate reference system used is WGS-84. I think the document is fine security wise. I have a couple of questions; mostly to satisfy curiosity: 3.4.3. Location Uncertainty The 'u' ("uncertainty") parameter indicates the amount of uncertainty in the location as a value in meters. Where a 'geo' URI is used to identify the location of a particular object, indicates the uncertainty with which the identified location of the subject is known. The 'u' parameter is optional and it can appear only once. If it is not specified, this indicates that uncertainty is unknown or unspecified. If the intent is to indicate a specific point in space, MAY be set to zero. Zero uncertainty and absent uncertainty are never the same thing. Shouldn't this MAY be a MUST? (since as you note zero uncertainty and absent uncertainty are never the same thing.) 3.4.4. URI Comparison Two 'geo' URIs are equal when they use the same CRS, and , , and 'u' value are mathematically identical (including absent meaning undefined 'u' value). Hmm. About comparison: I understand that when is present you are delimiting a sphere of radius centered on the point (, , ). When is absent (undefined) the sphere containing can have any radius, thus two geo URIs with same coordinates but undefined might correspond to a different spheres in which case it seems to me that they shouldn't be said to be equal. 5. URI Operations Currently, just one operation on a 'geo' URI is defined - location dereference: In that operation, a client dereferences the URI by extracting the geographical coordinates from the URI path component . Further use of those coordinates (and the uncertainty value from ) is then up to the application processing the URI, and might depend on the context of the URI. It seems that the document is also defining an equality comparison operation between geo URIs. --julien