Spent a couple of days this week flying the new DJI Matrice 4E in Hampshire. The task was to capture orthomosaic data for the WildPosh Grand Challenge project and involved a fair bit of prep with lots of support from Leo (Royal Holloway / UCL) and Matti (Reading) to get farmers permissions and flight locations. But even given lots of site analysis work on Google and OS maps, plus test flights locally to get the work flow for data capture sorted, I still fell at the first hurdle.
Turns out pretty much all the sites were slopey. I have obviously lost my knack of reading contours since they didn’t seem so bad on the map! The issue was that I had previously been working on a small patch of land that didn’t have much height variation (about 1m end to end) so I hadn’t noticed that the area route was not automatically adjusting the height of the drone (I thought it was). Turns out I had a flag set to height based on hone point. So the first route the drone was merrily flying towards the slope and I was wondering when it would start climbing- it didn’t - it just sat in the air beeping warning of an imminent collision.
Two thirds of a battery later and with the help of Gemini I realised that I needed to configure AGL (Above Ground Level) and after failed attempts to try to create a local map I ended up connecting the controller to my phone and downloading a DSM file for the area. This all worked fine but does have an impact on the GSD which went from a planned 0.33 up to 0.67 (and 0.9 when using the terrain follow function which uses the onboard vision sensors).
Got there in the end. 43GB data captured, 40GB looks useful to be processed. Just over 2 hours flying time, about 17km flown. Leo was also capturing transact data at each location so that we have a reference when we come to do the data analysis. You can see him working away with his tape measure in the video below.
I used OpenMTP to get screen grab off controller (for first time) which could be really handy for teaching. Video below.
Video screen capture coming in to land at OSR04
Next up, processing the data in DJI Terra and Metashape. Photos tagged with “Wildposh” on Flickr below.
