What is Horizontal Map Alignment?
Horizontal Map Alignment shifts and rotates a processed map to match a trusted reference map. You pick matching points on both maps, and DroneDeploy calculates the correction and saves it to the map. The tool changes the horizontal (XY) position only. It does not change elevation, and it does not scale or skew the map.
In the app, the tool appears as Map position (XY) in the map details panel.
Use Horizontal Map Alignment to:
- Compare maps from different dates more easily, because changes on site line up from one map to the next
- Keep overlays aligned on every map in a project
- Recover a map when a GCP is covered or RTK/PPK corrections fail, so the capture stays useful for comparison
- Align Mobile 3D Scans processed with RTK to a drone map
Availability: Who has access?
- Horizontal Map Alignment is an Open Beta feature available to all customers.
- To use it, turn on the New Explore page beta toggle.
- Saved alignments also display in the previous Explore page.
- You need permission to edit the map you align.
How to align a map
- Turn on the New Explore page beta toggle at the top right of the project and view the map you want to align.
- Open the map details panel.
- Under Accuracy, find Map position (XY) and click Align to another map.
- Choose the reference map. The reference map is the map you trust for position. The map you selected moves to match it.
- Add matching point pairs. Place one point on the map you are aligning and the matching point on the reference map. Add at least 3 and up to 9 distinct pairs.
- Wait for DroneDeploy to calculate the fit, then select the blue apply the alignment button at the bottom right.
- Review the result and reload the map to confirm the alignment saved.
Tips for picking points
- Treat the points like GCPs. Use clear features such as corners and center points that you can identify on both maps.
- Spread points across the site instead of clustering them in one area.
Key details
Alignment error does not equal accuracy
A low alignment error (root mean square error, or RMSE) means your point pairs fit each other well. It does not mean the map is accurate in the real world. DroneDeploy does not recalculate GCP or checkpoint reports after you move a map. Horizontal Map Alignment improves consistency between maps and does not establish survey accuracy.
What moves and what stays
- The map imagery moves.
- Annotations and crop polygons stay in place. Review existing annotations and crop polygons after you align a map.
- Measurements use the aligned map, so review existing measurement boundaries and results.
- New exports use the saved alignment. Regenerate any export you need in the new position.
- Elevation stays the same. Use Calibrate elevation under Elevation (Z) to adjust vertical position. Existing elevation calibration is preserved (Understanding Elevation Data
Mobile 3D Scans
Mobile 3D Scans processed with RTK produce 2D maps. You can align these maps to a drone map the same way you align any other map. Choose points that you can identify on both the scan map and the drone map, and use more than 2 pairs when you can.
3D outputs
Horizontal Map Alignment corrects the 2D map. Check any 3D output, such as the 3D mesh or point cloud, after you align a map. 3D views may not match the 2D map in the same way, so confirm the result in your workflow before you rely on it.
Undo an alignment
Alignment is not a permanent change to the map. You can click the Reset button without the need to reprocess.
Automatic and manual alignment
DroneDeploy aligns new maps to earlier maps of the same site automatically. See Automatic Map Alignment for details. Use Horizontal Map Alignment when a map still does not line up with the map you want to compare against.
Limitations
- You align maps to other maps only. Alignment to DXF files, IFC files, drawings and basemaps is not available.
- You align one map at a time.
- The tool corrects horizontal position and rotation only. Scale and skew stay the same.
- Horizontal Map Alignment does not replace surveyed ground control or independent accuracy checks. For high-accuracy work, see Choosing a High Accuracy Workflow.
Troubleshooting
- Align to another map is missing: Confirm that the New Explore page beta toggle is on and that you have permission to edit the map.
- The alignment does not apply: Add at least 3 distinct point pairs and wait for the fit calculation to finish. Replace any points that sit on top of each other or on a spot that does not match on both maps.
- The map fits one area but not another: Confirm that you chose the right reference map and spread your points across the whole site.
- The map looks distorted or has large errors that persist: Contact the Support team at support@dronedeploy.com with links to both maps and screenshots of the result.
FAQs
Q: Does Horizontal Map Alignment replace ground control?
A: No. It brings maps into agreement with each other. GCPs, RTK/PPK and checkpoints remain the way to establish and verify accuracy.
Q: Does Horizontal Map Alignment change my elevation data?
A: No. It changes horizontal position only. Use Calibrate elevation for vertical changes.
Q: Can I align a Mobile 3D Scan?
A: Yes, when the scan is processed with RTK. The scan produces a 2D map that you align to a drone map. Check any 3D outputs after you align.
Q: Do I have to reprocess my map?
A: No. The saved correction applies to the map without reprocessing.
Q: Can I undo an alignment?
A: Yes. You can reset the alignment without reprocessing the map.