[Open-transport] SBB - HAFAS --> GTFS Conversion

[Stefan de Konink]

On Mon, 28 Apr 2014, Patrick Brosi | geOps wrote:

> As Stefan pointed out correctly, frequency-based HAFAS connections 
> are skipped and, most importantly, each HAFAS-trip maps to a GTFS trip _and_ 
> a GTFS route. This is because we could not yet find a reliable mechanism to 
> create "real" GTFS routes without creating id collisions.

We have some ideas about this. But I agree this is an hairy issue.

As you may have observed the 'unique key' per Z-line isn't unique either 
(because is unique in combination with the bitfeld), but must be unique 
for GTFS, hence requires a new id.

You can do a distinct on routes, which we will be doing. But it requires a 
smart reverse mapping (for example with a CTE aggregation).

Stefan