Messages

1

General / Re: Relative accuracy with drone images withouth GCPs

« on: February 21, 2022, 08:40:45 PM »

Hi Paul,

Thank you for the help, please see attached the pdf and screen capture, hope this helps a bit.

Thank you,
Adam

2

General / Re: Relative accuracy with drone images withouth GCPs

« on: February 21, 2022, 12:49:20 PM »

The camera was around in an 80 degrees angle, so not in nadir, could it be the problem? There was also 1-2 meters difference with a shorter 8 meter parts as well. So, if I want to achieve maximum 10 cm error I would need GCPs or an RTK drone?
How can I tighten it up exactly with scale bars?

3

General / Re: Relative accuracy with drone images withouth GCPs

« on: February 20, 2022, 08:46:39 PM »

Hi dpitman!

Yes, a linear measurement on the 3D model and orthomosaic is off by at least a meter, I had reference measurements 41,7 meters long as well as an 8 meters one as well.
Sorry, I'm a newbie in this software as well as the measurements, but what does nadir mean?

Thank you,
Adam

4

General / Relative accuracy with drone images withouth GCPs

« on: February 17, 2022, 10:16:23 PM »

Hi All!

Currently my job is to measure rooftops with a maximum error of 10 cms. I have a DJI phantom 4 Pro V2 drone and I flew a reference building to see if I can produce accurate measurements. I used Pix4D capture with 3D model mission with 45 meters height and around 2 cm GSD and  80% front and side overlap and I had around 270 pictures. After importing and going through the aligning process and point cloud, mesh, textures and ortho photos, I had around 2-3 meters error in the measurements compared to the reference. What can I do, what did I do wrong? If you need more details, please ask for it.

Thank you for your help in advance,
Adam