GeoDrafter Pro Trace – tracing that just works
GeoDrafter Pro Trace is a free QGIS plugin for digitizing along existing lines and polygon edges. Click on a line and move the mouse: the path along the visible layers is traced and remembered as you go, so it does not jump to a nearby road or boundary. It needs no snapping setup, mixes tracing with freehand vertices and runs on QGIS 4 and QGIS 3.40.
Install
GeoDrafter Pro Trace is being tested in QGIS 4 before it is released in the official QGIS plugin catalogue. When it is approved, it can be installed in QGIS from Plugins ▸ Manage and Install Plugins by searching for “GeoDrafter Pro Trace”.
| Works with | QGIS 3.40 or newer, including QGIS 4.x (Qt6) |
|---|---|
| Price | Free |
| Licence | GNU GPL, version 2 or later |
| Telemetry | None – the plugin sends nothing anywhere |
What it does
Tracing saves you from clicking vertex by vertex when a new feature has to follow something that is already on the map: a parcel boundary, a stream, a road edge or the outline of a wetland. With Pro Trace you click once on a line, move the mouse along it, and the shortest path along the visible line and polygon layers follows the cursor. When you click again, that part is locked and you continue from there.
The trace is remembered while you move, step by step, instead of being recalculated from the last vertex. That matters on long, winding lines, where a shortest-path search from the start would cut across to a more direct road or boundary. Moving back pulls the trace back in. Clicking away from the lines adds an ordinary freehand vertex, so tracing and freehand can be mixed in the same feature.
How it differs from QGIS' built-in tracing
QGIS has its own tracing (Shift+T while digitizing), and it works well when snapping is set up for the right layers. Pro Trace takes a different approach in a few places.
| QGIS built-in tracing | GeoDrafter Pro Trace | |
|---|---|---|
| Snapping setup | Needs snapping enabled; traces only the snapping layers | None – own snapping on the line and polygon layers switched on in the Layers panel |
| Long winding lines | Shortest path from the last vertex; can jump to a more direct line | Follows the cursor and remembers the trace |
| Freehand | Toggle tracing on and off | Click off the lines for a freehand vertex |
| Nearly overlapping lines | The trace graph can silently come out empty | Lines are noded first; you are told if tracing is off |
| Many features | Turns off above a limit | Also has a limit (30,000 features in view) and asks you to zoom in |
How to use it
- Select the line or polygon layer you want to draw in. Editing starts automatically.
- Click Pro Trace on the GeoDrafter toolbar, or choose Plugins ▸ GeoDrafter ▸ Pro Trace.
- Click on a line, move along it and click to lock the traced part. Click off the lines to add a freehand vertex.
- Press Enter or right click to save the feature, Backspace to undo the last part and Esc to cancel.
Requirements and limits
Pro Trace needs QGIS 3.40 or newer, including QGIS 4.x. It draws into the active line or polygon layer in that layer's coordinate system. It traces only the line and polygon layers that are switched on in the Layers panel and shown at the current scale, so a layer is left out simply by unticking it. With more than 30,000 features in view it asks you to zoom in, so the map stays responsive. The plugin sends nothing anywhere and has no telemetry.
Questions
Do I need to turn on snapping in QGIS?
No. Pro Trace uses its own snapping on the vertices and edges of every visible line and polygon layer, independent of the project's snapping settings.
Can I use it on polygon layers?
Yes. You can trace along polygon edges and draw new features into a polygon layer as well as a line layer.
Is it free?
Yes. The plugin is free and open source under the GNU GPL, version 2 or later.