Segment Definition

This forum deals with any kind of routing computation whether it is simple A:B-routing, calculation of isochrones, simple matrix computation or nearest search.
Post Reply
g.fiume
Posts: 30
Joined: Wed Jan 25, 2017 9:17 am

Segment Definition

Post 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
User avatar
Bernd Welter
Site Admin
Posts: 2564
Joined: Mon Apr 14, 2014 10:28 am
Contact:

Re: Segment Definition

Post 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<br /><br />T : The top bar has to be treated as two segments as there is another 3-element node<br /><br />V : Could be seen as a single segment (without a node) or two separated segments.
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.
Bernd Welter
Technical Partner Manager Developer Components
PTV Logistics - Germany

Bernd at... The Forum,LinkedIn, Youtube, StackOverflow
I like the smell of PTV Developer in the morning... :twisted:
User avatar
Bernd Welter
Site Admin
Posts: 2564
Joined: Mon Apr 14, 2014 10:28 am
Contact:

Re: Segment Definition

Post by Bernd Welter »

Oh and there is another criteria (Thanks to our data expert Thomas E.) :D :
  • 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!
Bernd Welter
Technical Partner Manager Developer Components
PTV Logistics - Germany

Bernd at... The Forum,LinkedIn, Youtube, StackOverflow
I like the smell of PTV Developer in the morning... :twisted:
Post Reply