I am not sure how working in those fields relinquishes all doubt that the earth is round. Using an instrument that supposedly accounts for the curvature of the earth doesn't necessarily mean that it won't work if the earth was flat. Have you ever witnessed the horizon line form a bend? it is only natural that being higher up would allow for better visibility whether the earth was flat or round. I've been to the top of the empire state building and the horizon was still straight. What evidence is there of the earth being round? The only reason why I ever thought it was round was because that is what I was taught in school, but I have not actually seen true evidence of it. I am seriously leaning to the flat side of things. I've tried looking up a boat disappearing under the horizon on youtube and found this..
First of all in reality it is just "common knowledge" that the earth is a globe and has been a known and proven fact for centuries. And there is no evidence of a flat earth.
It is a moot point anyway.
All of the following prove curvature of the earth proving the earth is globe
In the Navy.:
Ships and land passing out of view over the horizon
Measurements to the horizon dependent on height of the observer
Range of radar on certain frequencies limited to line of sight and dependent on height of antenna
Crow's nest lookouts limits of sighting limited by height of crows nests
All navy charts and maps are made from projections of the globe of the entire earth
No maps are made from flat earth maps because there are no flat earth maps of the entire earth
In the FAA
Design of certain radars whose frequencies operate line of sight and range limit by distance to the horizon, also definite depending on height of radar antenna
Certain radio frequencies operate line of sight and limited by distance to horizon
Certain radio frequencies used on microwave repeaters also operate line of sight and limited by distance to horizon
Sectional charts and maps are made from projections of the globe of the entire earth
No such thing as flat earth maps as mentioned previously
These are just a few reasons why the earth is a globe.