Better to add lat/long for GCP before or after Align Photos step?

[ChrisC]

My photos do not have EXIF data, but I do have four ground control points with known lat/longs.  So should I do the Photo Align step first and then add in Markers with lat/long info, or should I add the Markers and lat/longs to the photos first before I do the initial alignment? 

I am new at this so please any help appreciated! Thanks.

[SAV]

Hi ChrisC,

It does not make a huge difference, but IMO it is easier to first align the pictures and then add markers because Photoscan will then be able to assist you with marker placement in the pictures because it already knows the 'spatial relationship' between the pictures.

Regards,
SAV

[ChrisC]

Thank you SAV! That makes sense now, I have noticed the blue flags showing up when adding markers after the alignment. Its a little bit of a pain to go and check them all, but it found some I may have missed otherwise too.

Cheers!

Chris