RTM:anchor

Introduction

See anchor in RailTopoModel^®'s wiki.

Documentation

Syntax

Autoexport from the XML-Schema for element RTM:anchor of railML® version 3.2 UML-visualization of RTM
Documentation	reference points for linear positioning systems, used for e.g. mileage changes
Subschema	Rtm4railml
Parents*	linearPositioningSystem
Children	None
Attributes: anchorName: Established, human-readable short string in natural language, giving the object a name. Not intended for machine interpretation (optional; xs:string), measure: for mileage anomalies: defined/shown mileage (optional; xs:double), measureToNext: measured distance from this mileage change until the next <anchor> point or until the end of the <netElement>. (optional; xs:double), id: the identifier of the object; this can be either of type xs:ID or UUID (obligatory; xs:string; patterns: (urn:uuid:)?[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}|{[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}}); compare: Dev:Identities
*Notice: Elements may have different parent elements. As a consequence they may be used in different contexts. Please, consider this as well as a user of this wiki as when developing this documentation further. Aspects that are only relevant with respect to one of several parents should be explained exclusively in the documentation of the respective parent element.

Autoexport from the XML-Schema for element RTM:anchor of railML® version 3.1 UML-visualization of RTM
Documentation	This element is not documented in the schema!
Subschema	Rtm4railml
Parents*	linearPositioningSystem
Children	None
Attributes: anchorName: This attribute is not documented in the schema! (optional; xs:string), measure: This attribute is not documented in the schema! (optional; xs:double), measureToNext: This attribute is not documented in the schema! (optional; xs:double), id: the identifier of the object; this can be either of type xs:ID or UUID (obligatory; xs:ID; patterns: (urn:uuid:)?[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}|{[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}}); compare: Dev:Identities
*Notice: Elements may have different parent elements. As a consequence they may be used in different contexts. Please, consider this as well as a user of this wiki as when developing this documentation further. Aspects that are only relevant with respect to one of several parents should be explained exclusively in the documentation of the respective parent element.

Changes 3.1→3.2

The element documentation has been changed.

The attributes have been changed.

Best Practice / Examples

In The RailTopoModel^® wiki <RTM:linearPositioningSystem> elements are the instances of a localization expressed in a linear reference system, generally a coordinate along a predefined axis. <RTM:linearPositioningSystem> is usually used to represent mileages of a railway lines. Please note that mileages can also be referred as “chainages” in the national regulations.

Due to historical reasons, the mileage (or "metering") of the tracks of a line often is not continuous. It can have any points of discontinuity (jumping with missing parts or overlength of tracks) for instance by geographical corrections / repositioning of a line.

The <RTM:anchor> and <IS:mileageChange> elements both can be used to define the position of a track where metering of mileage changes. The approach with <RTM:anchor> provides a more precise way because is able of compressed and stretched kilometers.

Refer to <IS:mileageChange> page for the alternative approach, relevant for when there is a need for an explicit IS element. See the discussion in forum.

Below you can see the source code of a representation of mileage change (overlap) through <RTM:anchor>.

<linearPositioningSystem id="lps01"
                         units="m"
                         startMeasure="0.0"
                         endMeasure="5000.0"
                         linearReferencingMethod="absolute">
  <name name="railway line 6869 positioning system"
        language="en"/>
  <anchor id="lps01_anc01"
          measure="1000.0"
          measureToNext="0"/>
  <anchor id="lps01_anc02"
          measure="990.0"
          measureToNext="4010.0"/>
</linearPositioningSystem>

Additional Information

Notes

See use cases for rtm:anchor (compressed/stretched kilometres, gap, overlap) in the guide .