I am referring to this very useful hack to change the color gradient of buffered polygons in order to show direction (with a gradient from red to green, for example)
The only problem is that data defined properties is no longer a button in QGIS. I am running 2.12. How do I get around this?
Here is an example of the lines that I want to fill with gradient color to show their direction:
Any other suggestions on how to show direction would be welcomed!
This is one of my attempts but actually the color gradients are random