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Segment Definition
Posted: Thu Jun 29, 2017 8:22 am
by g.fiume
Hi, I wasn't able to find on the manual how segment are calculated.
I've found this definition:
The roads of the routing network are divided at crossings and other important points into small road segments. Also ferries and piggy-back services are integrated as special segments in the routing network. When a route is calculated, each segment is assigned a mathematical cost value that can be influenced by a lot of parameters.
But isn't clear how PTV decide which points goes in a segment and which points goes in the next one. And so, why some segment are longer than others?
Thank you (again) for your help
Gianni
Re: Segment Definition
Posted: Tue Jul 04, 2017 12:05 pm
by Bernd Welter
Well, from my point of view I'd describe a segment as a sequence of points (sometimes just two, sometimes more) that is not interrupted by a crossing...
- P : the center of the left bar cannot be handeled as a single segment because it is connected to another element and therefore contains a crossing
T : The top bar has to be treated as two segments as there is another 3-element node
V : Could be seen as a single segment (without a node) or two separated segments.
Re: Segment Definition
Posted: Thu Jul 06, 2017 12:59 pm
by Bernd Welter
Oh and there is another criteria (Thanks to our data expert Thomas E.)
:
- A segment is a unit created by one of the data providers. The provider partitions the digital network based on his own rules.
- A segment is a unit which is based on the application of ISO certificate GDF based on defined critreria.
- Though a crossing is an important base object that has influence on the segment endpoints it is not the only one: changes of attributes on a segment (speed limits, streetname, linked to different administrative base element ...)
We are family!
Thanks Thomas!
Enjoy your holidays!