Q:

Showing which way line features are oriented in QGIS?

I'm working on QGIS on a street shp file which has Left From, Left To, Right From, Right To fields fields, building a geocoder.
I need to know which way these features are oriented, which I think is the same as knowing which of the two (or more) points that make the lines comes first.
Is there a way to automatically rotate a triangle marker on the marker line style so that it shows how the line is oriented?

A:

Simplest way is to style the line.  Add a new symbol layer to your line and change the 'Symbol Layer Type' to marker line.  Select 'Marker' in the style tree and select a triangle as your default marker symbol. I believe 'triangle 2' is your best bet. Accept these changes and all your lines will now have arrow showing the direction of the line.  You can mess around with distances and marker placement to make it look better but this essentially show you where your lines are going.

