Measurement tools
Measurement lives in the Cesium 3D mode (cesium3d) only. The 2D and Google Earth
3D modes don’t expose measurement tools in the current build. Open the
Measurement menu from the map tile toolbar and pick one of four modes.
The four modes
Ruler
Point-to-point great-circle distance + bearing.
- Click two points on the map.
- After the second click the tool auto-completes — no double-click needed.
- The result panel shows distance (metric + imperial) and bearing (degrees true north).
- Geometry: Haversine formula on the WGS-84 ellipsoid.
Path
Multi-point cumulative distance.
- Click each waypoint in order.
- Each segment’s distance appears inline; the cumulative total updates live.
- Double-click the last point (or single-click the first point) to finalise.
- Great for foot routes, planned vehicle paths, pre-flight walk-throughs.
Area
Polygonal area.
- Click each vertex of the polygon in order.
- Double-click the final vertex to close.
- Area is computed via Girard’s theorem for spherical excess — accurate even for polygons spanning tens of kilometres. Not a flat-Earth approximation.
- Result panel shows area in m², hectares, and km².
Elevation
Single-point elevation query.
- Click any point.
- The tool returns the terrain elevation at that lat/lng (meters AGL relative to the Cesium terrain provider — Photoreal tiles provide sub-metre terrain detail in cities).
- Useful for line-of-sight checks when planning drone altitudes.
What measurement does not do
- No save button. Measurements are ephemeral. Closing the measurement menu, switching tools, or switching map modes discards the result.
- No auto-flag. There’s no one-click “save this point / line / polygon as a flag” shortcut. If you need the coordinates preserved, drop a flag at the point manually and re-measure.
- No export. You can’t export a measurement as KML / GeoJSON. Take a screenshot if you need to share.
These are all reasonable follow-ups — file a ticket if they’d help.
Tips
- For LOS checks use the elevation tool on both endpoints then run a mental or calculator-based flat-earth LOS calculation, or compare against the drone’s planned altitude. A future “profile” tool is planned that will auto-graph terrain between two points.
- For SAR area planning use the Area tool to confirm a drawn SAR polygon is the size you expected before running the grid generator.
- For distance sanity checks the Ruler’s bearing output is useful for verifying a planned flight heading.
Combining with polygons + flags
Measurements don’t persist, but you can annotate a measurement by:
- Running the Ruler / Area tool.
- Reading off the value from the panel.
- Dropping a flag at one of the measurement points with the value typed into the flag’s message.
The flag survives across sessions; the measurement doesn’t.