Tracing feature in Earthlight is a feature which allows you to trace mouse cursor to alongside edges of a specified layer or group of layers. In tracing mode, you will be able to add nodes only alongside existing edges of geometries (unless the 'Allow non-traceable points' option is active in Trace settings) which you trace to.
To start using Trace feature, it is required to set trace layers first.
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After adding the second node, line or polygon will be created, using marked edge. You can continue drawing with the Trace option active or turn off the option and finish polygon or line outside the edge which was traced.
The result:
Additional trace settings:
- Snapping/tracing attraction radius (in pixels):
By adjusting this slider, you can choose how close to snapping points, you will have to move your cursor.
- Tracing zone radius (in pixels)
When active (set > 0px) creates circle zone around your cursor with specified radius. Tracing trail will be drawn only when the cursor is in it.
Without this option I can quickly move from one point on an edge to another, without actually following the edge.
When the option is active, tracing zone was created and if the cursor will be moved not alongside the edge, tracing trail will not be drawn.
With this option enabled, it is required to move cursor alongside a geometry edge, up to the next desired node location.
- Mask opacity:
Using this slider you can control opacity of the tracing mask, when the trace option is active.
You can configure the default Snap/Trace settings in the Global/Inheritable User Settings in Editing tab.
