Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

As title, I am working with pgRouting, trying to get the distance matrix along the river system.

I use driving_distance function and it seems like I am getting what I want: enter image description here

But when I check the result table below, the distances returned are right, but it doesn't return all sets of distance.

In my case, I have 159 segments in the river, but in the result table there are only 50 rows of distance. I have set the tolerance to a drastically huge number that can cover all the river network, and I've tried many other starting point but whatever I tried the maximum returned result is always 50 rows.

How to solve this strange problem?

I'm working under WIN7 64-bits, with postgreSQL 8.4, PostGIS 1.5.

share|improve this question
I have found out it's the problem that if I want to get all sets of distances, I need to split polylines into pieces uniformly. –  Heinz Jan 6 at 6:59
add comment

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.