GeoDrafter Measure – geodesic distance, area and radius in QGIS
GeoDrafter Measure is a free QGIS plugin that measures distances, areas and radius circles on the ellipsoid, so the result is right whatever the map projection. Finished measurements can stay on the map as layers with their values, be exported to a GeoPackage or copied, and they match GeoDrafter's web distance and area tools. It runs on QGIS 4 and QGIS 3.40.
Install
GeoDrafter Measure 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 Measure”.
| 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
The plugin has three modes. Distance gives the total length of the line you click and the length of each segment. Area gives the area and perimeter of the polygon you click. Radius draws a circle around a centre point, either by dragging with the mouse or by typing a radius such as 5 km, 3 mi or 2 NM and placing the circle with one click.
Every measurement is made on the ellipsoid of the project, or WGS84 when the project has none, not in the flat map projection. On a Web Mercator map at 60° north, flat distances come out twice as long as on the ground and areas four times as large; geodesic measurements do not have that error. The radius circle is a true geodesic circle, so every point on it is the same distance from the centre on the ground.
Keep, export and copy the results
Keep on map adds finished measurements to the layers GeoDrafter distances and GeoDrafter areas, with the values as attributes, so they can be styled, labelled and saved with the project. Export saves the same layers to a GeoPackage. Copy puts the current result on the clipboard. Units can be metric, imperial or one fixed unit.
The calculations match GeoDrafter's web tools, so a distance measured in QGIS gives the same number as the distance calculator, the area calculator or the radius map in the browser. That makes it easy to check a value with someone who does not have QGIS.
How to use it
- Click Measure on the GeoDrafter toolbar, or choose Plugins ▸ GeoDrafter ▸ Measure, and pick a mode in the panel.
- Click points on the map. Right click, double click or Enter finishes; Backspace removes the last point; Esc clears.
- In radius mode, drag from the centre, or type a radius and click once where the centre should be.
- Use Keep on map, Export or Copy to save the result.
Requirements
Measure needs QGIS 3.40 or newer, including QGIS 4.x. It works in any project coordinate system. The plugin sends nothing anywhere and has no telemetry.
Questions
Why does Measure give a different number than measuring in the map units?
Because it measures on the ellipsoid, as the ground really is, while a measurement in map units is distorted by the projection. In projections such as Web Mercator the difference can be large.
Can I draw a buffer of an exact distance?
Yes. In radius mode, type the distance, for example 5 km, and click once on the centre. The circle is drawn geodesically and can be kept on the map as a polygon.
Is it free?
Yes. The plugin is free and open source under the GNU GPL, version 2 or later.