Hello there

I'm starting to fly with a Phantom4, my main objective is 3D terrain modelling for scientific research (I'm a geologist and university professor).

Although we can find several options (paid and free, like Lichi, Autopilot, Pix4Dmapper, Altizure, DroneDeploy, etc) for mission planning focused on 2D/3D mapping where the aircraft is -above- the terrain, I couldn't find anything for a near-vertical target, like a cliff. In this case, I would expect the aircraft to fly parallel to the cliff face at a given height, then go down a bit, fly parallel again and so on. Much like a 2D grid but 'vertical'. Also, since the camera of the P4 doesn't rotate around the Z axis, it might be necessary to fly 'sideways', pointing the camera towards the cliff.

Does anyone have any experience on this? Indications of apps/techniques?

TIA

CarlosGrohmann:

You can, in my experience, do that with Litchi (it does allow WP altitude settings), but you have to program each waypoint individually, and yes, you would have to fly sideways. This could be a perilous undertaking, considering the varying shape of the face, the distance to the ground, drafts and turbulence, not to mention trying to maintain a consistent distance from the face, likely not a completely flat one.

It's conceivable that if your rockface is perfectly round, (tublular or conic), that you could use POI mode, but perfect circles rarely occur in natural formations. And even then, taking pictures in POI mode would likely be a manual operation.

So, if you can keep a large margin of distance between the quad and the rockface, you could program Litchi to do it, relatively safely.

Keep Smiling,

Augustus

Have you tried DJI Ground Station Pro

Have you considered creating a path with Google Earth and pull it into Litchi? You  could offset if from the face , have it take pics or constant video, etc.

DJI-Ken Posted at 2017-3-31 12:03
Have you tried DJI Ground Station Pro

Hi. I've been looking into this and I think GSpro can be the way. I can set a polygon area for mapping, adjust the flight azimuth angle. I'll go on a field trip next week to test all this. When I return I will report.

CarlosGrohmann Posted at 2017-4-3 11:05
Hi. I've been looking into this and I think GSpro can be the way. I can set a polygon area for mapping, adjust the flight azimuth angle. I'll go on a field trip next week to test all this. When I return I will report.

Sounds good, let us know what you think.

DJI-Ken Posted at 2017-4-3 12:19
Sounds good, let us know what you think.

Ok, I'm back from the field trip, and I can share some thoughts on this now.

During the field campaign, I used GSPro, Pix4Dcapture and Altizure on different occasions. Generally speaking, GSPro performed better, but there is room for improvement.

Pix4D failed to complete the mission more than once (the drone completed the flight, but it didn't took all the pictures) because it was 'too far' from the home point (more than 150 meters).

Altizure is a bit weird. Although it has nice setups for the mission planning, it flys the drone 'sideways', so you get the landing gear in almost all images...

GSPro has nice features, but it could benefit from:

- more than one provider of sat imagery in base map - in one area we were working, Bing maps were full of clouds, and only Google had (low-res) cloud-free imagery. Being able to select the imagery provider would be a big plus.

- more clear indicators about drone+camera orientation in mission planning - the 'course angle' option sets not only the flight angle, but also the camera orientation. So if you have flight lines oriented 45º, the camera will always point to 45º, and the drone will fly forward and backward in this direction, instead of flying forward to 45º, making a turn to the next line, and then flying forward to 225º (the opposite of 45º). This is not a deal breaker, although it is not well documented. Maybe adding little arrow symbols in the flight lines (not only at start/end) would help. Also, the angle is using a cartesian notation, where 0 degrees is East, 90º is North and so on. Since we are working with geographically-positioned targets, using an azimuthal notation would be more natural. Anyway, flying in the usual forward-turn-forward would be better.

- better transfer speed when uploading the mission - I noticed the both Pix4D and Altizure send the mission to the drone way faster than GSPro. As a side note, I also noticed that when the tablet gets hot, mission upload gets really slow or doesn’t work at all.

- better control of settings - the sliders are not the best option if one wants to fine-tune any of the settings, such as course angle or overlap (especially on a small tablet as the ipad mini - imagine on a phone). Being able to tap over the numerical field and typing the desired value would help a lot.

- shoot pictures in RAW - in DJI Go 4, I can set the app to take pictures in JPEG and RAW, but not in GSPro. This is a must for professional-level 3D mapping.

- an option to show the footprint of pictures would be great. I guess that the app from mapsmadeeasy.com does this but I couldn’t test it.

- add an option to set the start/end points, regardless of flight orientation (I’d like to have the bird always start the mission at the farthest point and end it closer to the home point)

That’s what I can remember at the moment

best

Carlos

CarlosGrohmann:

What attributes disqualified Litchi?

Keep Smiling,

Augustus

Augustus Brian Posted at 2017-4-20 19:18
CarlosGrohmann:

What attributes disqualified Litchi?

Hello Augusts

In the end I didn't used Lichi mostly because I didn't had the time to learn it and test it before the field trip. Hopefully for a next trip I'll be able to use it.

CarlosGrohmann Posted at 2017-4-20 18:39
Ok, I'm back from the field trip, and I can share some thoughts on this now.

During the field campaign, I used GSPro, Pix4Dcapture and Altizure on different occasions. Generally speaking, GSPro performed better, but there is room for improvement.

That's great input, in the ME section of the GO app you can leave feedback if you like.