Skip to main content
Solved

ShortestPathFinder problem

  • February 6, 2017
  • 9 replies
  • 37 views
G

I have a simple workflow trying to find a shortest path between 2 points. I am using a Cook County (Chicago) road network and a Creator to enter from and to points. In spite of different snap distances I keep getting an error "No shortest path found from...".

My workflow is attached and the network file is from:

https://catalog.data.gov/dataset/tiger-line-shapefile-2013-county-cook-county-il-all-roads-county-based-shapefile

TIA,

George

Best answer by takashi

Hi @gjgorczynski, the ShortestPathFinder requires the network lines are noded properly, but the download data seems not to be so. Consider using the TopologyBuilder (Assume Clean Data: No) to make a network consisting of lines connecting each other at their end nodes.

This post is closed to further activity.
It may be an old question, an answered question, an implemented idea, or a notification-only post.
Please check post dates before relying on any information in a question or answer.
For follow-up or related questions, please post a new question or idea.
If there is a genuine update to be made, please contact us and request that the post is reopened.

9 replies

erik_jan
Contributor
Forum|alt.badge.img+23
  • erik_janContributor
  • Contributor
  • February 6, 2017

I see you created the line with coordinate system LL84.

Is the Shape file you are using in the same coordinate system?

If the Shape file does not have coordinate system information, you might want to use the CoordinateSystemSetter transformer to assign a coordinate system.

I would check the data sources using two inspector transformers to see if they match (location).

takashi
Celebrity
  • takashiCelebrity
  • Best Answer
  • February 6, 2017

Hi @gjgorczynski, the ShortestPathFinder requires the network lines are noded properly, but the download data seems not to be so. Consider using the TopologyBuilder (Assume Clean Data: No) to make a network consisting of lines connecting each other at their end nodes.

Why not inspect features with Visual/Data Preview and Feature/Record Information before writing them into a destination dataset?
itay
Supporter
Forum|alt.badge.img+18
  • itaySupporter
  • Supporter
  • February 6, 2017

I totally agree with @takashi it's the first thing that I would check...

G

Hi @gjgorczynski, the ShortestPathFinder requires the network lines are noded properly, but the download data seems not to be so. Consider using the TopologyBuilder (Assume Clean Data: No) to make a network consisting of lines connecting each other at their end nodes.

Perfect! TopologyBuilder fixed it. Thank you @takashi. How did you know that the lines were not noded properly?

 

G

I see you created the line with coordinate system LL84.

Is the Shape file you are using in the same coordinate system?

If the Shape file does not have coordinate system information, you might want to use the CoordinateSystemSetter transformer to assign a coordinate system.

I would check the data sources using two inspector transformers to see if they match (location).

Thanks for the suggestion @erik_jan.

 

takashi
Celebrity
  • takashiCelebrity
  • February 6, 2017
Perfect! TopologyBuilder fixed it. Thank you @takashi. How did you know that the lines were not noded properly?

 

Just had a look at the data with FME Data Inspector ;-)

 

Why not inspect features with Visual/Data Preview and Feature/Record Information before writing them into a destination dataset?
G
Just had a look at the data with FME Data Inspector ;-)

 

I think I know what you mean, there should be nodes at all intersections. Thanks again, I'm totally new to FME.
david_r
Celebrity
  • david_rCelebrity
  • February 7, 2017
I think I know what you mean, there should be nodes at all intersections. Thanks again, I'm totally new to FME.
That is spot on, there has to be a node at all the allowed intersections for the ShortestPathFinder to consider them.
itay
Supporter
Forum|alt.badge.img+18
  • itaySupporter
  • Supporter
  • February 7, 2017
I think I know what you mean, there should be nodes at all intersections. Thanks again, I'm totally new to FME.
I would strongly advise reading on the transformer used to understand its working and needed input. Each transformer has a Help button that will open up the help page where this information can be found.

 

 

"Input line features must be a topologically noded network with features connecting at line ends only. That is, all features must be split at junctions."

 

 

Hope this helps and happy FME'ing!

Community Stats

32,154
Posts
122,047
Replies
39,812
Members

Latest FME

Terms & ConditionsCookie settingsAccessibility statement
A product of
Safe Software respectfully acknowledges that we live, learn and work on the traditional and unceded territories of the Kwantlen, Katzie, and Semiahmoo First Nations.