Estimated Marker Projections not Showing Up

[iaerobotics]

Work flow is to align images. They I convert coordinates to NAD83(2011) to match my ground control. Then I import ground control and have it create markers. Markers show up in their perfect position on the Model view, but when selecting a nearby image and opening it, it does not show the markers on the image so you can confirm or adjust. If I "Place Marker" on 2 images and perform a camera calibration, then "Filter Images by Marker" it will show all the images with the grey flag that I can quickly confirm / adjust. But I have to do this for every marker and it very time consuming.

Is my workflow wrong? Does converting the coordinate system break the automatic marker projection?

I am using a DJI Phantom 4 that comes in at WGS84 but all my ground control is in NAD83(2011).

[Alexey Pasumansky]

Hello iaerobotics,

If the initial coordinate system for cameras is WGS84, then it is expected that altitude values are defined over the ellipsoid. If the altitude is measure over geoid, you should use WGS84+EGM96 coordinate system instead.
In case the altitude is measured over the take off point, you may need to input the initial height correction for all cameras before placing markers.

Alternatively, you can define 2-3 projections for 3-4 markers in the way that you are doing it now, then uncheck cameras, check on all markers and press Update button on the Reference pane.

[iaerobotics]

Thanks for the response. Shouldn't the "convert" take care of that when I convert the cameras to NAD82(2011)? I would rather not have to convert the ground control from NAD83(2011) to WGS before importing and then convert it all back and verify alignment.

Is there a better workflow that would allow me to see the estimated flags without having to manually "place" 2 markers? That about triples the time to mark control based.

Thanks for the help.

[Alexey Pasumansky]

Hello iaerobotics,

If the source coordinate system for the cameras is selected incorrectly (WGS84 instead of WGS84+EGM96, for example), then the conversion result will be also incorrect.

To solve the issue you need to fix the altitude issue first (before converting the camera coordinates or loading the markers). Maybe the information in the following article would be helpful: https://agisoft.freshdesk.com/support/solutions/articles/31000152491-working-with-dji-photos-altitude-problem-
And you can just add the fixed value to all the camera altitudes using the script and proceed with the common marker placement workflow.

[iaerobotics]

Bingo - thank you sir. Converted to WGS84+EGM96, then converted to StatePlane (NAD83(2011)), then used the script (after changing to allow to run on 1.6) to adjust the altitude, update transform, calibrate camera and they show up now.

A suggestion if possible would be to remove the check for altitude - since most the time if xy match up, you can place the marker and then when you calibrate adjust for Z. This may mess up other workflows though where there are multiple layers involved and you only want to show if the marker is very close already to the adjustment layer.

Thanks for the help. Much better.