Low Altitude Mapping

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Hello All,

I am looking for a software that let's my Phantom 4 pro to fly on a pre-planned course and the altitude could be set below 10 meters. Preferably 5-6 meters max.
I tried Pix4D but it limits the altitude to minimum of 10 meters. Are there any alternatives? I need one which works with Phantom 4.
I have different drones like Yuneec and others and they have their softwares for it, but so far I could not find a good one for DJI.

Thank you!
Gabe
 
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You can set the Phantom to the Follow terrain mode and fly as high as you want. But I don't know how accurate is this.
 
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DJI's Ground Station Pro (GS Pro) allows you to flight at 16.4 feet (5 m), but it only runs in iOS.
Measure (gc.measure.com) also allows you to flight at 16.4 feet.
Both can be used for free, and they also have paid versions.

I'm just curious, Why do you need to map at such low altitude?
If you are mapping a large area, you will end up processing thousands of pictures and the file size will be very difficult to manage.
If the area is small, one picture from 100' - 200' (30 - 60 m) could capture a lot of details.
 
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Why are you mapping at 15' to 20' AGL (5 - 6 meters)? You will need 70 - 80% overlap in all pictures, so even a small area will require a massive amount of pictures to process. There are many good reasons to map at 200' AGL (61 meters), and that is probably why your software won't let you map at 5 meters.
 
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Hi, I use Litchi to fly pre-programmed routes over crops such as maize and wheat. The missions are repeated every 3-4 weeks throughout the growing season. As the maize emerges I fly as low as 6 feet agl and then increase the height as the plants develop. But of course I am taking video rather than photos. As for mapping at low level have you looked at Hivemapper which uses Litchi missions to produce 3-D mapping from video?

I too am very curious why you want to map as such low levels. I don't think it will actually be possible using photos because of the time time it takes to process and store the photos and you would need to move the drone so slooooowly.

All the best, Martin
 
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Hello All,

I am looking for a software that let's my Phantom 4 pro to fly on a pre-planned course and the altitude could be set below 10 meters. Preferably 5-6 meters max.
I'm curious about the kind of mapping you are wanting to do too.
When you fly at 70+ metres, the difference between adjacent images in small and stitching is easy.
But if you fly at only 5 metres, you would have to fly slowly to capture images close enough together for stitching them to be possible.
 
Hello All,

Thank you for the responses.
The reason for me flying at this low altitude is that I need to make good quality photos of crop fields, with the lowest GSD possible.
The images are processed by a software to analyse the different weed and crop types. This is for research and testing purposes so luckily, I only need to fly above a small area.
 
DJI's Ground Station Pro (GS Pro) allows you to flight at 16.4 feet (5 m), but it only runs in iOS.
Measure (gc.measure.com) also allows you to flight at 16.4 feet.
Both can be used for free, and they also have paid versions.

I'm just curious, Why do you need to map at such low altitude?
If you are mapping a large area, you will end up processing thousands of pictures and the file size will be very difficult to manage.
If the area is small, one picture from 100' - 200' (30 - 60 m) could capture a lot of details.
I'm going to guess he's not mapping.

D
 
Hello All,

Thank you for the responses.
The reason for me flying at this low altitude is that I need to make good quality photos of crop fields, with the lowest GSD possible.
The images are processed by a software to analyse the different weed and crop types. This is for research and testing purposes so luckily, I only need to fly above a small area.
Shooting your highest resolution @ 100' AGL should give you lots of detail. I can almost read a license plate @ 250' AGL. I see that you're shooting crops. At 100' you can zoom in on a mouse. So unless you are scrutinizing individual kernels of corn, 100' (30 meters) should work extremely well.

Here's a screen capture from 4K (UHD) video @340' AGL. The roof is about 40' high, for a net difference of 300'. Now imagine your still photos (which would net a higher resolution) @ 100' AGL. From this shot we can see a bucket. From 100' AGL I would be able to tell you what's IN the bucket.

1638472216195.png


D
 
Last edited:
hey check out my tool for Litchi
it's hosted at ancient.land

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video shows how to use it but I'll quickly explain all the buttons available at the moment

Home - Sets home point, where the drone is expected to take off in order to conform to elevation from DEM
Target - Draw your polygon
Rotating Arrows - Switches between the drone turning 180 degrees after every line or facing one way only (spin by default)
Moon - Photo footprint layer
Disk - Save as Litchi csv file which you can import in their mission hub and fly from their app.

Also in the hamburger menu there's Z-Check which substitutes waypoints for photos on the go. Used in flat areas to keep the drone moving.

Obviously wouldn't recommend flying this low especially if you're around trees or undulating areas where a generic DEM isn't detailed enough to keep you as high as you need.
 

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