---
layout: example.html
title: Tracing around a polygon
shortdesc: Using the draw interaction to trace around features.
docs: >
The draw interaction has a trace
option to enable tracing
around existing features. This example uses the traceSource
option
to trace features from one source and add them to another source. The first click
on an edge of the target feature will start tracing. The second click on the edge
will stop tracing.
tags: "draw, trace, vector, snap, topology"
---