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General / Re: Control points with aerial surveys
« on: December 27, 2022, 01:21:34 AM »
@Apavlicek - I'm going to answer based on my understanding of your question. I'm concerned I may be misunderstanding your intention and if I've answered wrong, please let me know and I'll clarify.
In Metashape, all Points (Lat/Lon coordinates) used for reference are stored together. You can choose to make them either "Control Points" or "Check Points"
When you choose to make them "Control Points", they are used to rectify/correct the alignment to achieve better accuracy.
When you choose to make some of these "Check Points", these will not be used to rectify/correct Metashape's processing.
Imagine you have a project shaped like a vertical rectangle. Imagine you have 6 reference points in that image (four near the corners, one near the top-center and one near the bottom center). In this example, imagine you set your corner points as Control Points. You then set your center top/bottom points as Check Points.
The four Control Points will help rectify the output and if everything is correct, the two Check Points should be matched.
If they are not matched, there are two things you can do with Check Points. One, you can use them to help determine where there is an error elsewhere, keeping them as Check Points. Two, if you are 100% certain the Check Points are more accurate than Metashape's output, then you could choose to convert them into Control Points (forcing the output to use them to correct its output).
If the Check Points match, there is nothing more to be done with them. They are not used, or needed, and nothing else you will do in the future with those points (other than re-confirm if you move anything around and re-align in the future).
Does that make sense?
In Metashape, all Points (Lat/Lon coordinates) used for reference are stored together. You can choose to make them either "Control Points" or "Check Points"
When you choose to make them "Control Points", they are used to rectify/correct the alignment to achieve better accuracy.
When you choose to make some of these "Check Points", these will not be used to rectify/correct Metashape's processing.
Imagine you have a project shaped like a vertical rectangle. Imagine you have 6 reference points in that image (four near the corners, one near the top-center and one near the bottom center). In this example, imagine you set your corner points as Control Points. You then set your center top/bottom points as Check Points.
The four Control Points will help rectify the output and if everything is correct, the two Check Points should be matched.
If they are not matched, there are two things you can do with Check Points. One, you can use them to help determine where there is an error elsewhere, keeping them as Check Points. Two, if you are 100% certain the Check Points are more accurate than Metashape's output, then you could choose to convert them into Control Points (forcing the output to use them to correct its output).
If the Check Points match, there is nothing more to be done with them. They are not used, or needed, and nothing else you will do in the future with those points (other than re-confirm if you move anything around and re-align in the future).
Does that make sense?