Setting Markers for Ground Control Points Process

[Ashura]

Hi all,

I want to use my GCPs to set the accuracy for my UAV photos.... I already have them geotagged using telemetry data but I have many GCPs which I recorded in the field and I'd like to use them to over-ride the telemetry accuracy.

This is my first time attempting it with agisoft.... I am assuming before I do anything in workflow I should be placing my markers beforehand in agisoft... is this correct?

Thanks!

Alex

[James]

Often it is better to place your markers after initial image alignment as photoscan will estimate where your markers should go after you place each one in 2 images.

You can even align images and then build mesh based on sparse cloud and photoscan will estimate the position of each marker after you place it in 1 image.

Using either approach you can then whip through marker placement quickly by placing each marker in 1 or 2 images, then filter images by selected marker, and use page up and page down to flick through the images and photoscan will center each image on the expected marker location (with a little grey or blue (if you built the mesh already) icon) allowing you to place it quickly.

[James]

Also I think you can override the telemetry data by unchecking the cameras in the reference pane and clicking update (once you have entered the gcps), followed by optimise if required.

[Ashura]

Also I think you can override the telemetry data by unchecking the cameras in the reference pane and clicking update (once you have entered the gcps), followed by optimise if required.

Thanks so much James- this is a huge help! I am gonna give it a try in a few days with my new imagery- I will update.

Alex

[frank.stremke]

hi
you can also set teh precision values acording to real world so you can still use your data but it is considered and weighted acording to the precision so if you give your camerea accuracy as 10 or 15 m which should be fine for a not to fast flying uav then the data is of course given much less value then your few mm or cm accuracy of the GCP
this is done in  the settings at the reference pane
frank