Advice for surveying large areas

asisel · Feb 22, 2017

Hi everyone,

Does anyone have experience and/or know-how to compensate for the uavs flying altitude over hilly topography? I would like the uav to stay "somewhat" consistent with the topography. Right now, I am using pix4dcapture to do all my flight planning. Any advice would help! Thanks!

Richard R · Feb 22, 2017

The latest version to the Litchi app (iOS version) has a feature that allows you to adjust waypoint heights to local terrain.

FreeBerd · Feb 23, 2017

asisel said:
Hi everyone,

Does anyone have experience and/or know-how to compensate for the uavs flying altitude over hilly topography? I would like the uav to stay "somewhat" consistent with the topography. Right now, I am using pix4dcapture to do all my flight planning. Any advice would help! Thanks!

The DRONES MADE EASY app, I believe its called MAP PILOT has terrain follow capability. I have not used. I believe it costs extra. I assume you are looking to create ortho and DSM and/or contours? Ground control?

Meta4 · Feb 23, 2017

asisel said:
Hi everyone,

Does anyone have experience and/or know-how to compensate for the uavs flying altitude over hilly topography? I would like the uav to stay "somewhat" consistent with the topography. Right now, I am using pix4dcapture to do all my flight planning. Any advice would help!

There's no need to vary your altitude for topography if you are creating orthophotos.
Just make sure you will be clear of the highest points.

asisel · Feb 26, 2017

Meta4 said:
There's no need to vary your altitude for topography if you are creating orthophotos.
Just make sure you will be clear of the highest points.

I would usually agree with you but I have only asked because this is what I got from pix4D. (Image Acquisition Plan for Terrain with Height Variations). Let me know your thoughts on that.

Thanks!

Meta4 · Feb 26, 2017

asisel said:
I would usually agree with you but I have only asked because this is what I got from pix4D. (Image Acquisition Plan for Terrain with Height Variations). Let me know your thoughts on that.

That looks like it's something that Pix4d have come up with. I haven't seen it from anyone else.
How much variation is there in the terrain on the site? Is it enough to have to worry about?
How could you fly a survey that goes high over high parts of the site?
If you were to fly with an acceptable overlap over the high parts of the site, the overlap would be even more in lower parts.
If the variation in elevation isn't serious, it shouldn't be an issue.

Richard R · Feb 26, 2017

The article is correct, but the question is, as Meta4 stated, how much does it matter? I recently flew 2 missions over the same are using the Maps Made Easy app. The first at 400 ft with a 1.9 inch GSD and the second at about 200 gave me a 1 inch GSD. So unless the terrain that I was mapping varied by much more than 100 ft within the area of interest, I would fly at a nominal a height that gave me the resolution desired over the primary area of interest. Having said that, I may have to check out that in-app purchase mentioned by freeberd.
Update. Just checked. The latest version of Map Pilot (came out 2 days ago) has the 'terrain aware' feature that allows for maintaining a constant height above ground. Time for me to fire up the tablet and update.