add new script reverse_markers.py

[jasonrmh]

This script will reverse the current marker selection.

[PolarNick239]

Hello!

In which cases it is convenient to reverse markers selection? I would like to understand how often this can happen to other users.

P.S. Sorry for the long reply.

[jasonrmh]

My use for this script was so that I could select markers for GCP's, then mark remaining markers for use as check points.
Example:
I have 10 markers.
I select 5 to use as CGP's. I mark photos for each marker.
I then reverse markers, which means now the check point markers are selected.
I can now mark photos in the remaining 5 markers.
Now I can reverse markers again, leaving GCP markers selected to continue processing, check accuracy etc.

Hope that makes sense?

[PolarNick239]

I have 10 markers.
I select 5 to use as CGP's. I mark photos for each marker.
I then reverse markers, which means now the check point markers are selected.
I can now mark photos in the remaining 5 markers.

Hmm, but can't the same thing be achieved in a simpler way? F.e.:

1. Create 10 markers
2. Place their projections in all photos
3. And then select 5 GCPs from them

How does enabling/disabling markers affect the placement of marker projections in photos? Aren't they independent?

[jasonrmh]

After importing reference file, I will de select markers to use as checkpoint, mark photos for GCP's, update transformations.
I then reverse markers, allow me to mark photos for the markers I want to use as check points, but I do not update transform based on check points.
You can't mark photos unless a marker is selected.

For checkpoints, I do not update transformation, to ensure they are truly independant and giving me a more realistic accuracy value.

So to recap with a bit more detail:

• Import references
• I have 10 markers (all selected by default)
• I de select 5 to use as check points.
• I mark photos for each selected marker (GCPs).
• Update transform after I have completed marking photos for a single marker.
• I then reverse markers, which means now the check point markers are selected.
• I can now mark photos in the remaining 5 markers.
• Now I can reverse markers again, leaving GCP markers selected to continue processing, check accuracy etc.

If I didnt have my script, on sites where I have 10 - 20 GCP's, I would have to manually select / deselect markers when switching from marking GCP's / Checkpoints. With the script its a single click of the menu, regardless of how many markers I have.

This the the workflow I am following from this video, which prompted me to create the script, to save time selecting deselecting markers.
https://youtu.be/ytvc0euMeKM?si=Dvgk4wiBFJP7LDcS&t=558

[PolarNick239]

But if I correctly understand - your workflow will also work in the following way without the script:

1. Import references
2. you have 10 markers (all selected by default)
3. mark photos for all markers
4. de select 5 to use as check points
5. Update transform
6. continue processing, check accuracy etc.

Am I missing something?

P.S. this is not so important, but I also don't fully understand this - You can't mark photos unless a marker is selected. - you mean that Filter Photos by Markers doesn't work if a marker is de-selected? But it works for me - I opened a random project, un-selected the marker and Filter Photos by Markers worked as expected - only relevant photos were shown in the Photos pane below.