On 12.01.2011 16:40, Michał Borsuk wrote:
Am 12.01.2011 16:30, schrieb ant:
Consider an application that takes a start and an end address, maybe
other options such as night lines only, and that shall calculate the
shortest PT connection including number of stops etc. How would you
accomplish that with the old tagging scheme?
By introducing an abstract interface layer with your own objects, that
is your own internal standard, into which all the "messy" present
standards would be translated. This is easy. Then you play with *your*
objects, your program is not directly dependent on the OSM PT standards.
Any changes to the standards will require only a few lines of code to
the abstract interface layer.
There are some minimum requirements that the data should meet in order
to make it easy. In particular, it should resemble the network structure
of a PT network, i.e. bus and tram stops acting as nodes that connect
bus and tram lines with each other. A node in this context means "a
place where i can change from one bus (tram) line to another without
having to walk more than a few metres". In the proposed scheme a stop
area is exactly this. So the point of stop area relations is to prepare
the data to be interpreted as a network and thus to make routing... easy.
cheers
ant
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