Open Geospatial Consortium
OGC Doc 09-022
CR-Form-v3
CHANGE REQUEST
GML CR 09-022
rev-
Current version: 3.2.1 For
HELP
on using this form, see bottom of this page or look at the pop-up text over the symbols.Proposed change affects: AS X Imp Spec X Best Practices Paper Other
Title: GML Linear Referencing Support
A (corresponds to a correction in an earlier release)
B (Addition of feature),
C (Functional modification of feature)
D (Editorial modification)
Detailed explanations of the above categories can be found in the TC Policies and Procedures.
Reason for change: ISO TC211 19148 Linear referencing has now reached CD stage
Summary of change: Add GML support for Linear referencing types specified in 19148
Consequences if
not approved:
GML would remain deficient in an important capability necessary to support an extensive amount of (mostly Transportation) data but also with implications in other industries, such as piping.
Clauses affected:
Other specs X Other core specifications ISO 19148 Linear referencing
GML Linear Referencing 08-022
GML (and other OGC specifications) currently support 2- and 3-D spatial locations. An alternative location scheme is to use linearly referenced locations, where a location is specified as being at a certain distance along (and perhaps offset from) a linear element. The linear element might be a feature which exhibits linear behaviour (e.g., is linearly measurable), a curve type of geometry, or a directed edge type of topology.
A significant amount of historical data is currently linearly referenced, especially in the transportation and piping industries. There are advantages of using this scheme over (or in addition to) spatial referencing.
Just as spatial data may utilize a variety of spatial (coordinate) reference systems, linearly referenced locations use a wide variety of Linear Referencing Methods (LRM). A well documented theoretical basis has been developed to support many of the more common LRMs in practice internationally today. ISO TC211 has undertaken the task of developing a linear referencing standard based on this Generalized Model for Linear Referencing. The ISO 19148 standard has now reached a more stable CD status.
It is therefore time to begin supporting linear referencing within OGC. This document proposes extending the OGC Abstract Specification and GML to support linear referencing consistent with 19148.
