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DATEX-II-EU / DatexII

Main repository for issues and bugs for the DATEXII standard
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[Feature]: Possibility to add a unit of measure for distance expressions in linear referencing #547

Open LBlaive opened 1 week ago

LBlaive commented 1 week ago

Feature description

In the current version of Datex II, the distance expressions used in the linear referencing methods (absolute or relative) only use metres as unit of measure. To comply with EN ISO 19148, it would be useful to allow different units of measure for distances like e.g. miles. To allow for this it is necessary to replace the current data type ("MetresAsFloat") of "distanceAlong" by "Float", add a new attribute "unit" of "UnitOfMeasureEnum" enuneration. This approach could also be used for cases where alternative units of measure would be desirable (e.g. for traffic regulations with distances or currencies).

LBlaive commented 1 week ago

Indeed the "UnitOfMeasureEnum" enumeration is currently present in the "Vms" namespace. It would be worth moving it to the "Common" namespace. Indeed this construction is used for the "VmsPublication" package ("DisplayedNumericalInformation" class).

iancornwell1 commented 4 days ago

Even although I come from a country that uses miles, I'm not sure such a change is beneficial overall. UK DATEX II implementations have always been content to use metric units for distance in location references. It would add cost for all implementations to have to check units and potentially convert. Referring to a displayed speed regulation is another matter, where the case for exact reproduction of signs is stronger.