Horz. and vert. accuracy of pics and geolocation error

PIX4Dmatic
1

Hi,

I’ve started using Pix4Dmatic and I’m missing two features (closely related) that are available in Pix4Dmapper:

  • When selecting the input images, you could select horizontal and vertical accuracy of the pictures, depending on how these pictures were generated (GPS/RTK/GCPs…). How is this now selected? Is any default value automatically selected?
  • A quality report was generated after the initial processing step. Here, absolute and relative geolocation variance information was included, which was useful to determine the precision of the model. Haven’t found this info in Pix4Dmatic… Is it no longer available?

Thanks in advance!

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2

Hi @ja.pelaez, thanks for bringing this up.

My answers below:

Accuracy values for pictures

Right now, when there is no information in the EXIF/Xmp of the images about the horizontal and vertical accuracy of the pictures, default accuracy values of 5m (horizontal) and 10m (vertical) are set like in Pix4Dmapper.

If the recommended EXIF/Xmp tags for horizontal and vertical accuracy of images are available, then these are read and used instead of the default values.

These are the tags regarding accuracy:

  • for geolocation: Xmp.Camera.GPSXYAccuracy and Xmp.Camera.GPSZAccuracy

  • for orientation: Xmp.Camera.IMUYawAccuracy, Xmp.Camera.IMUPitchAccuracy, Xmp.Camera.IMURollAccuracy.

All EXIF/Xmp tags read by Pix4Dmatic are listed here: https://support.pix4d.com/hc/en-us/articles/205732309-EXIF-and-XMP-tag-information-read-by-Pix4D. As long as the required tags are in the images, the camera is compatible with Pix4Dmatic, more in https://support.pix4d.com/hc/en-us/articles/360037744571-Which-cameras-are-supported-in-Pix4Dmatic.

Note that we are working on a .csv import of geolocation and orientation data, that will help set new values for the accuracies if they are not available in the Xmp data of the images. Once this import is available, we will also work on a table that shows all the geolocation and orientation data, so that this workflow becomes more transparent.

Quality report: absolute and relative geolocation variance

Here is the current content of the quality report: https://support.pix4d.com/hc/en-us/articles/360040686852-Quality-report-Pix4Dmatic

The values you are asking are not available for the moment, but we plan to work on a more extensive quality report. Your request is noted. Do you have examples when these values are particularly useful? This will help illustrate the need for these values.

Thanks!

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Hi @Pierangelo_Rothenbuhler,

Okay, thanks for the information. Regarding the report, I don’t have any concrete example, but some customers have required us these values in ceratin works, mainly when building models for airport environments.

Thanks again and kind regards.

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