Messages

76

General / Z-axis scalebar for Volume measurement

« on: May 09, 2018, 08:36:39 PM »

Hi all,
Would it be beneficial to run some sort of z-axis scalebar for volume measurement or are the xy-axis scalebars enough ?
Thinking of a pole or similar with 2 coded targets on, or something along those lines.

77

General / Re: Altitude used in Processing UAV (DJI Phantom 4 Pro)

« on: May 06, 2018, 11:19:09 PM »

SAV,

Thank you very much for explanation and links!
Much appreciated.

78

General / Re: Altitude used in Processing UAV (DJI Phantom 4 Pro)

« on: May 04, 2018, 03:56:31 PM »

How will an RTK equipped drone, using no GCP's or Scale Bars do? Comparable to RTK GCP's?

The time consumed by placing and measuring out GCP's seem to worry my clients, as it is considered downtime, where heavy machinery can't operate as freely a usual.

79

General / Area calculation - Only getting perimeter measure

« on: April 24, 2018, 11:57:00 AM »

Hi!
I trying to measure the area of a roof, but I can only get the perimeter measurement.
I select the polygon, right-click -> Measure.

What am I doing wrong?

See screenshots

80

General / Re: Using Yaw Pitch Roll from DJI Drones

« on: April 20, 2018, 02:42:52 PM »

Hello doctorben,

So you need to load Gimbal angles to the Reference pane?

Then just use

Code: [Select]

camera.reference.rotation = (yaw, pitch, roll)where yaw, pitch and roll values are read from the image header.

How do I relate to a specific imagefile, when using your script to extract the information?

81

General / Re: Using scale bars for Pile volume measurement

« on: April 20, 2018, 12:12:08 PM »

Thanks! I will try out a few things !

I have been looking at the Emlid solutions for a while, might pull the trigger at some point.

82

General / Re: Using scale bars for Pile volume measurement

« on: April 19, 2018, 11:54:07 PM »

that's what I said. drone deploy is right. GCP are not strictly required for stock pile measurements... but a few distances are a must if you want obtain decent quantity numbers.
Do the same pile volume estimation from two different flights without using scale bars and you will probably find out that quantities can change quite significantly from flight to flight

Once you add good scale bars, the role of on board gnss will become mostly negligible. keep in mind that by default camera positions are supposed to be as accurate as 10m, while scale bars are usually supposed to be in the range of a few mm accurate.
Lastly I'd kindly suggest you that as long as you don't want or can't afford to use surveying methods for ground control, do not give away any so-called "orthomap", not even as extra... or if you do so, please call it mosaic, or collage, or whatever that is far enough from surveying & mapping glossary...

Thank you very much for your time and explanation. I will go out and do some tests in the weekend.

83

General / Re: Using scale bars for Pile volume measurement

« on: April 18, 2018, 11:24:33 PM »

If you can measure 3 or more long distances and your works are solely aimed to volume estimations, then you can probably get same accuracy as withe 3D ground control points. However you should be careful avoiding extrapolated areas that are far from the area enclosed (more or less) by your distance measurements.

My primary purpose would be to measure the volume of a given stockpile. I might throw in the 3D render & orthomap, just for extra content, but not something customer expects nor requires.

So if I layout 6-8 point around the pile, and do as many measurements between those 8 points as possible?
Of course I will still use the GNSS on the drone combined with the scale-bars. From whitepapers on the subject, it seems that some of the position inaccuracy can be averaged out by very substantial overlap (>90%).

Interestingly enough, Dronedeploys guide on stockpiles actually explicitly say that GCP's are not needed: https://support.dronedeploy.com/docs/volume-measurement

What is Your guys experience with that?

84

General / Re: Using scale bars for Pile volume measurement

« on: April 18, 2018, 11:15:43 PM »

How do you fix height with your distance meter ? This job needs a lot of known xyz points to be accurate.

Well, that's part of my question

85

General / Using scale bars for Pile volume measurement

« on: April 18, 2018, 05:47:45 PM »

Hi all,

Currently evaluating Photoscan as a tool in my UAV business.
I don't have access to RTK precision GCP eqiupment, but I do have a very accurate Laser range-finder. Can I use that in combination with coded targets and scalebars instead of a RTK GNSS solution?
What will the precision be compared to RTK, if I can measure the scalebars to within 1 mm pr 10 meters?