ok so this has been bugging me for a few days and i cant figure out whats going on. flying a Mavic 3 Enterprise with DroneDeploy, set up a grid mission targeting 2cm GSD at 70% front and side overlap, the planner said i should be cruising at something like 55m AGL. went out, flew the mission, processed fine but when i check the outputs the actual GSD is coming out closer to 3.2-3.4cm. not a huge deal for this particular job but i want to understand what im missing.

the terrain wasnt totally flat, there were some elevation variations maybe 8-10m across the site but i had terrain following turned on so i thought that would handle it. is this a focal length thing, like is DD using the right sensor specs for the M3E camera. or am i just misunderstanding how GSD works in practice versus in the planner. i fly fairly regularly but photogrammetry is still kinda new to me

terrain following helps but it doesnt always keep you perfectly at target AGL over the whole site, theres usually some lag or smoothing happening so if you had rolling terrain you were probably a bit higher than 55m for portions of the flight. also worth double checking that DD has the right focal length dialed in for whichever lens you were using on the M3E, i think there was a period where the wide vs tele settings were getting mixed up in older versions of the app

yeah GSD calculators are always a bit optimistic lol. the math is clean in theory but real world you have wind affecting ground speed slightly, terrain follow isnt pixel perfect, and sometimes the camera specs in the planner are just slightly off. 3.2cm from a 2cm target at 55m isnt terrible honestly, for most deliverables thats not gonna matter. if you were targeting survey-grade stuff thats a different conversation but construction progress shots at that resolution are totally fine

also just curious are you using the nadir lens or did you have the tele on there, because that would explain basically everything