Hi All,

I've moved along quite a bit with my P4 RTK and Agras T20, and have successfully mapped and sprayed about 50 acres or so. It's been a good learning experience, and the actual spraying results were excellent. If I was a paying customer I'd be happy, and that's what this will be all about soon as my licenses are close to completion.

I'd like to do a bit better with my mapping though, in particular my settings on my P4 RTK.

My first maps were at 1.5 pix/cm, and it's a bit hard to make out the finer branches on trees etc. My associate is using a Matrice 300, and his maps at 1 pix/cm are (obviously) much better. I realize he has much better/faster hardware, but I'd like to map at the same resolution even if it takes longer.

I'm wondering if someone here can take me through the settings and give me a list of what will work best for my drone. I'm not looking for cinematography or survey grade, just good maps that will work well in Terra Ag for the purpose of spraying with an Agras T20/T30/T40 drone.

Things like distortion correction... on or off? I think Terra Ag does it when reconstructing, but I'm not sure.

White balance (or was that exposure)... Cloudy, sunny or farmland? And do I set that in camera settings or when I actually plan the mission?

But basically I'm hoping someone would be kind enough to take me through, step by step and set this P4 RTK up with a simple/solid set of values that works for my application. I'm using the basic controller with the built in screen and app, which is fine for me. I've also got a more advanced controller that runs a tablet and external mapping apps, but I want to learn the basics first.

I'm actually a real farmer with a very good knowledge of the local weeds and the chemicals used to control them. I hope to be a successful drone spraying contractor.

Thanks very much in advance for any help offered.

And what exactly is the "farmland" setting? I can't find anything about it on the internet. Is that a one size fits all setting for open land that doesn't care if it's cloudy or sunny? That would be handy.

if you simply want finer GSD then you can adjust the altitude in GS RTK until you get what you want, or use a calculator like https://www.propelleraero.com/gsd-calculator/ to figure it out (for 1 cm GSD, you want 35-40 m AGL w/ the P4R). As you know, the lower you fly, the longer it takes to map a given area. And if you get super low (< 15 m AGL) , you'll want to slow down as well.

Regarding camera settings, you set those independently of planning the mission, and the defaults are usually fine unless you know better. If you think you need to improve on the results you get with the defaults, try tweaking the settings systematically and comparing the outcomes.

patiam Posted at 3-18 12:11
if you simply want finer GSD then you can adjust the altitude in GS RTK until you get what you want, or use a calculator like https://www.propelleraero.com/gsd-calculator/ to figure it out (for 1 cm GSD, you want 35-40 m AGL w/ the P4R). As you know, the lower you fly, the longer it takes to map a given area. And if you get super low (< 15 m AGL) , you'll want to slow down as well.

Regarding camera settings, you set those independently of planning the mission, and the defaults are usually fine unless you know better. If you think you need to improve on the results you get with the defaults, try tweaking the settings systematically and comparing the outcomes.

Thank you,

I've found at exactly 40m I'm at 1.1pix/cm. It's a good height on farmland for clearing all the trees.

When planning the mission it does have the option for camera settings, and I do leave them as default with the exception of white balance, due to the weather conditions on the day.

I generally use "Sunny" as I don't try to map on cloudy days, but I am wondering about trying the "Farmland" setting as farmland is what I'm mapping. There's literally no mention of this setting anywhere, I can't find a single example of anyone using it.

This recent map I just did went very wrong, with weird distortion lines all through it. I think I may have turned on the distortion correction, which is off by default. I'll wait till my new charger arrives and try again, I can't keep up with the batteries.

Back again with this. Tried everything.. bumped up overlap from 70/80 to 75/85. Speed at 7km/hr. Height @ 53m (1.4 pix/cm). Distortion correction off.

Any ideas what's causing this?

Try another processing software application. Pix4D, Agisoft, et. all have trial versions.

Back again.

Basically I've been told it's just different color due to clouds, sun changing position etc and is normal.

It's had no effect on planning fields for the spray drone, so I'm fine with the stripes. I'm not doing photography as such.