I'm working on a map showing oil shipping. Basically, I have a a series of nodes/line segments that make up the shipping network. I've joined the sums of oil that traveled along each node, so can show how much oil is traveling over those nodes.

How can I show the directional breakdown along each node? In other words, I'm trying to show the split each segment by the direction of the oil on it, showing that with different colors and having the pen width adjust to the size of the flow in that direction.

Edit: Could this be done with two layers, one of which is given a data-defined offset based on the width of the other layer, such that they line up with eachother?

enter image description here

Multiple layer version: enter image description here

  • Could you share a sample of the data for test purposes? In general, I think it's going to work better with only one layer instead of two.
    – underdark
    Jul 22, 2014 at 16:34

1 Answer 1


I may have a solution for you. If flow in one direction is consistently lower than in the other direction, this would work. I think you have much of the answer included in the question. I would attempt to duplicate the layer and draw the limited flow on top of the greater flow and have them both symbolized by the flow value.

  • Thanks! I've played around with doing duplicate layers a little. The hitch is then you have overlap, which I think is less effective at showing the volume passing on that node. Do you know of any easy way to offset one of the layers such that it would line up with the border of the other flow? I haven't figured anything out like that yet. Here's a link to the layered version: imgur.com/2qMfPmD
    – aabramow
    Jul 21, 2014 at 19:46

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