Support Website Contact Support Blog

GCP does not match altitude

Hello folks. Can please someone help me? I am having problems with the GCP and Raycloud in step1. The project has 9 GCPs and only one is not macthing the altitude of the GCP and Raycloud. The others are fine. 
I already did reoptimization and still the same. The difference is about 9.2 metters. Please see the image. Thanks guys


here is the Quality Report. I’m wonder about the blocks. Is too many. Is normal? 

Many blocks is meaning that the project are not accurate or poor?

What the meaning of many blocks?

Hi Sammia,

Thank your for the screenshots.

The Quality Check section of the quality report is very useful, as it informs of existing issues in a project. In your case, there are issues with the dataset calibration and the GCP error: all images should have been successfully calibrated, in one single block, and the RMS error should be lower than 2*GSD. See the article sections linked to these errors hereand here.

It is important to address these errors first, because it is probable the offset issue with GCP no. 3 will be solved as a result. Indeed, the blocks were created by the software, because there were not enough matches between them for a global optimization. The blocks are not aligned, which is why some areas do not fit your GCPs. 

However, without more information about your project, it is hard to point to a specific cause for the uncalibrated images.

  • Could you please provide us with a link to you quality report (Google Drive, Dropbox, etc.), as well as 5 consecutive images from your dataset? 
  • Also, does the dataset consist of images from different flights?

Looking forward to your answer.