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：
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.