Some tests using the DJI GS Pro (Ground Station) software for automatic flight programming with the Phantom 4 Pro.
New flight campaign at the Kuckenburg spot (Sachsen-Anhalt) finished with two different flight altitudes using DJI GS Pro – mapping the open archaeological excavation site of medieval church now in September 2017. This worked flawless – the only problem: you kind of need a mobile connection with your iPad. Since DJI GS is an iPad-only software I used a hotspot from the iPhone to bring the iPad online. Its not perfect but it works. Overall I find DJI GS Pro to be more easy to program and to setup than Drone Deploy. The interface has more option to setup – so it is at first more complex but it integrates into the DJI Go App and so far my impression is that it is not giving these unexplained copter start problems that Drone Deploy sometimes showed. GS also seems to be less integrated into a subscription model and looks like a standalone software solution – though a DJI account is needed. I havnt tested capturing DNGs. Its not a direct option as far as I can see – this could be a limitation. You can easily modify exposure times and f-stop numbers even when flying to geht sharper shots. There is however so far no option to switch from JPEG to DNG. As this is usually only limited by bandwidth it could be an option that is available when you decrease the flight speed (leaving enough time between exposures) – so not tested yet.
As an in-App purchase you also can automatically do POI flights – this is very handy for these dense point clouds of single objects and its not so straight forward to do this in manually POI mode as part of the DJI GO software (though also possible).
DJI GS Pro however has some strange ways to handle waypoints when you use the hover method but once you understand where the problem is (the number of waypoints is restricted to 99) – it works nicely. DJI GS Pro also comes with different modi – “Virtual Fence” is very nice for training and restricting the flight space, “3D-Map Area” is for mapping of larger areas and “3D Map POI” is for these POI flights where you want to map 3D object structures and where you have enough space between objects to create some kind of circumnavigation.
The full manual goes here: https://dl.djicdn.com/downloads/groundstation_pro/20170831/GS_Pro_User_Manual_EN_V1.8.pdf
Some shots from the Kuckenburg flight campaign with 500 DNG shots and approx. 50Mio and 80Mio points in different dense point cloud calculations with Agisoft. As we don’t have a SAPOS subscription for “Sachsen-Anhalt” no DGPS points were measured. However some fixed points from the FSU Jena excavation team will be used.
For some of the copter data processing folks Agisoft Photoscan turns out to be the most important tool to calculate point clouds, orthoimages and nadir data mosaics. Problem: very long processing times with dense point cloud calculations with high or ultra-high settings (full resolution image matching with SfM (Structure from Motion) algorithms).
Some nice net finds show how multicore processing has its limits and why you should invest into GPU performance … and in high end 3D graphic hardware.
Combining more than 20 CPU cores doesnt seem to speed up the process and combining more than 4 GPU systems also doesnt seem to help. There is only a minimal speed increase when you add more CPUs and/or more GPUs when a 24 core system is already installed.
It boils down to a dedicated system with 2-4 Graphic cards with 3D acceleration (GTX-1080ti cards from Nvidea), with approx 64-128 GB RAM and a dual i7 system setup.
mtk – Sören
Using DroneDeploy and the POI mode of DJI.
Have been doing some leaf-off flights now in March on one of my favorite sites for complex tree crown point cloud mapping. To add to the leaf-on data from last autumn.
Fig.: Leaf-Off point cloud with combined height color coding and reflectance color coding.
This time I also checked the full automatic flight modi using the POI (Point Of Interest) mode from DJI and Drone Deploy with the P4Pro and the P3A.
Both work perfectly although I believe the POI mode can be dangerous when its done with low altitudes. You have to carefully check that the radius is free from obstacles when you define the center position, altitude and distance from center (radius) for the POI flight. When POI is started it begins with comparably low speeds. You can modify the speed setting when the POI mode started. Unfortunately you cannot modify this stetting before you start. Tuning the speed on an iPad or (even more difficult – on an iPhone) is kind of dangerous because you easily move the slide too much to higher speeds than wanted and the copter will immediately accelerate and start circling your POI object like crazy until you managed to move the slider to slower speeds. There is however always this stop button to kill the POI mode – this is handy and needed sometimes. When you press the stop button the copter stops the POI mode completely and waits for new commands.
Continue reading “Using DroneDeploy and the POI mode for automatic point cloud mapping”
Short point cloud animation from a decid forest stand shot with the P3A system in September. Processed with Agisoft Photoscan and corrected/visualized with QT-Modeller.