data under bridges

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

We were recently shooting an accident scene that went under a bridge using a DJI Mavic Enterprise 2. When we started processing, we found that all of our images taken under the bridge had no GPS data. The bridge is approximately 155 feet across then a 15 foot gap and then a second bridge that is 115 feet across. We have tried using manual tie points to connect the photos together with no results.

  1. Is there a way to tie these photos with no data to our photos with data so it can be processed into the ray cloud or enough to make an orthomosiac?

  2. Does anyone know of away to fly the mission under the bridge and the drone to receive the GPS data to get the data to be able to map it?

Thanks.

2

Hi John,
When you select the standard calibration method during step 1 it actually doesn’t use the GPS coordinates to calibrate the images. So I would think it should still work under the bridge. Have you tried processing it yet and if so can you attach the quality report?

3

Pix 4d no with no GPS_report.pdf (1.5 MB)
I tried rerunning the processing again and this is the quality report file. We laddered down and then flew under the bridge with the camera at 45 degrees flying with camera facing opposite directions in a back and forth path. I can see where it enters and exits from underneath the bridge, but all of the photos underneath are unclassified.

4

Hi John,
I’m a little unsure what you are trying to do. Did you fly a grid above the bridge then flew a manual flight below the bridge as well? The reason I ask is because the small orthomosaic shows imagery of the top of the bridge.