Internet Engineering Task Force (IETF) J. Winterbottom
Request for Comments: 5964 M. Thomson
Category: Standards Track Andrew Corporation
ISSN: 2070-1721 August 2010
Specifying Holes in Location-to-Service Translation (LoST)
Service Boundaries
Abstract
This document describes how holes can be specified in geodetic
service boundaries. One means of implementing a search solution in a
service database, such as one might provide with a Location-to-
Service Translation (LoST) server, is described.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5964.
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Winterbottom & Thomson Standards Track [Page 1]
RFC 5964 Service Boundary Holes August 2010
Table of Contents
1. Introduction ....................................................2
2. Terminology .....................................................3
3. Specifying Holes ................................................3
4. GML Polygons ....................................................6
5. Holes in GML Polygons ...........................................6
6. Service Boundary Specification and Selection Algorithm ..........7
7. Security Considerations ........................................10
8. Acknowledgements ...............................................10
9. References .....................................................10
9.1. Normative References ......................................10
9.2. Informative References ....................................10
1. Introduction
The LoST protocol [RFC5222] maps service and locations to destination
addresses. A LoST server does this by provisioning boundary maps or
areas against service URNs. The boundary is a polygon made up of
sets of geodetic coordinates specifying an enclosed area. In some
circumstances, an area enclosed by a polygon, also known as an
exterior polygon, may contain exception areas, or holes, that for the
same service must yield a different destination to that described by
the larger area.
This document describes a profile of Geographic Markup Language (GML)
[ISO-19107] polygons that constrains their representation when used
for describing service boundaries. The profile removes a number of
permutations that are difficult to process. This allows for
simplified implementations that are not capable of handling all
potential variations allowed by GML. A fully conformant GML
implementation must produce polygons that fit this profile to ensure
interoperability.
Winterbottom & Thomson Standards Track [Page 2]
RFC 5964 Service Boundary Holes August 2010
o--------------o
/ \
/ /\ \
/ + +-----+ \
o | Hole \ o
| | 1 / |
| +-------+ |<--- Primary Polygon
| +-------+ |
| / Hole | |
o \ 2 | o
\ +-----+ + /
\ \/ /
\ /
o--------------o
Figure 1: Holes in a Polygon
This document describes a profile of GML [ISO-19107] polygons that
constrains their representation when used for describing service
boundaries.
The working group considered that the types of regions described in
datatracker.ietf.org