Centralised EPSG codes (de: übergreifende Angabe von EPSG-Codes)

Description

Background

It was mentioned by Dirk Bräuer that the definition of EPSG codes for every geoCoord element provides redundancy and enlarges the railML files. Therefore, it is suggested to define an attribute for a global EPSG code being valid for all coordinates of the railML file. By adding an EPSG code to a single geoCoord element, this EPSG codes overwrites the defined global EPSG code.

Initial proposal:

<infrastructure ... defaultEpsgCode='4326' defaultHeightEpsgCode='5783'...> 

Deutsche Kurzfassung

Dirk Bräuer hat angemerkt, dass die Angabe von EPSG-Codes für jedes einzelne geoCoord-Objekt zu einer Redundanz und unnötigen Vergrößerung der railML-Dateien führt. Es wird vorgeschlagen, ein Attribut für die Angabe eines übergreifend geltenden EPSG-Codes einzuführen.

Links

• Forum discussion:
• Trac tickets:
• Wiki documentation:

Proposed solution for railML 3.1

railML 3.1 implementation includes a separation of coordinates and coordinate systems. Thus, the EPSG code is defined in a central place being valid for all the coordinates referencing this coordinate system.

The following example of a level crossing shows the general concept of separation:

<positioning>
  <geometricPositioningSystems>
    <geometricPositioningSystem id="gps01" crsDefinition="epsg:4326" name="WGS84"/>
  </geometricPositioningSystems>
</positioning>
...
<levelCrossings>
  <levelCrossing id="lcr01" ...>
    <spotLocation id="lcr01_sloc01">
      <geometricCoordinate positioningSystemRef="gps01" x="10.58775" y="52.26128"/>
    </spotLocation>
  </levelCrossing>
</levelCrossings>