ok so this has been bugging me for a few days and i need someone to tell me if i made a rookie mistake or if this is just a known limitation i wasnt aware of.

did my first paid survey job last week, small agricultural parcel, maybe 40 acres, client wanted an ortho and elevation model for drainage planning. flew a grid mission with my mini 4 pro, 80/75 overlap, 120m AGL, around midday which i know wasnt ideal but the client needed it done that day.

loaded everything into webodm and the orthomosaic came out pretty decent in the middle of the field but the edges are a mess, like the stitching just falls apart along two sides and there are these weird blurry seam lines. i added maybe 5-10% buffer beyond the boundary which apparently wasnt enough? also the elevation model has this doming effect in the center that i read about after the fact ? the classic dome artifact from flying without GCPs.

i dont have an RTK drone and wasnt using any ground control points because i honestly didnt think it would matter that much for a drainage analysis. the client hasnt complained yet but im looking at this thing and its not what i wanted to deliver. is the dome thing going to actually affect their drainage calcs or is it subtle enough that it wont matter at this scale

the dome artifact on 40 acres without GCPs can be pretty significant yeah, ive seen it throw elevation values off by 20-30cm in the center vs edges which is absolutely going to mess with a drainage analysis if theyre trying to figure out where water actually flows. its not subtle at that scale unfortunately.

for future jobs even 3 or 4 GCPs measured with a decent GNSS receiver makes a huge difference, you dont need RTK on the drone itself. checkered targets from amazon and a rented survey GPS for an hour is way cheaper than a redo. also your edge artifacts are almost certianly from not enough buffer, i usually do at least 15-20% beyond the AOI especially on windy days where the aircraft might be slightly crabbing.

midday lighting probably didnt help the stitching on the edges either, harsh shadows and blown highlights make it hard for the feature matching to lock on consistently. not the main issue but worth knowing for next time