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Accuracy

Hi.
Using Trimble UX5 drone I have collected photos of pit site and processed it with Pix4Dmapper Pro Trial, UASMaster Lite and Agisoft photoscan Pro.
Report from Pix4D http://www.filedropper.com/krivaiciaireport

Point cloud files was imported in AutoCAD Civil 3D software. And TIN surfaces was
compared. Most of site was in 1-3 GSD accuracy, but not all. Location on a slope have up to 4 meter difference. And it was steep slope. So, accuracy depends on the steepness of the slope? And how much it depends?

I have processed photos using Pix4Dmapper Pro few times and compared results. Got the same results as comparing Pix4Dmapper results with other software results.

So if I process photos with Pix4Dmapper Pro many times with same settings I will get different results? Different in flat location will be 1-3 GSD and in steep slopes will be big?

Hello Donatas,

Could you please directly attach the Quality Report to this post? We couldn’t get it from your link.

The error of 1-3 times the GSD in the vertical direction (1-2 times the GSD horizontally) only applies to projects having GCPs.
Is that your case?

Besides the overlap, GSD, image geotaggs, and GCPs, the visual quality of the images also impacts on the accuracy.
For instance good lightning conditions, clearness i.e. without blur, but also in terms of content, e.g. sharp edges, reflective surfaces, certain type of roads and rooftops may present lower accuracy locally.

If you are not satisfied by the reconstruction of some 3D points in your model, like in steep slope areas, you could add Manual Tie Points (MTPs) in order to locally improve the accuracy: https://support.pix4d.com/hc/en-us/articles/202560349

More about accuracy and precision of the outputs: https://support.pix4d.com/hc/en-us/articles/202558889

Best regards,

Hi Donatas and Pix 4d support:

I am trying to use Pix4d mapper pro to processes photos acquired from  Trimble UX5 HP UAS. The photos iself do not have geotags as the geotags are stored in a separate file. This is thus different from analyzing photos acquired by DJI drones.

 

I am wondering if there is a document or online reference that I can look up on how to process ux5 hp data with Pix4d? 

Thank you!

Hi Niti,

It is possible to import a geolocation file when there is no geotag written in the image EXIF. Just make sure the file complies with the Pix4D format requirements. More information: https://support.pix4d.com/hc/en-us/articles/202558539

Regards,