So I can start here real quick. People can check my math in case I made some error.

We are told that the radius the earth is approximately 6,378km at the equator and 6,357km at the poles (due to their claim that the earth is an oblate spheroid).

But km is not granular enough, so let's convert these down to meters (we'll probably never get accuracy to feet).

6,378km =6,378,000 meters (poles)

6,357km =6,357,000 meters (equator)

Let's say we're looking at Las Vegas. It's neither at the poles nor at the equator, so let's just for now take the average between these two, which would be:

6,367,500 meters.

So we can use that for our radius of the earth.

But Las Vegas has an average elevation of about 2,030 feet or about 619 meters. So we'll add that to the previous radius and get ...

6,368,119 meters as our R value.

So we have 2 sides of our triangle at 6,368,119 meters.

We would determine the 3rd side of our initial triangle by getting the distance between the bases of two buildings (converted into meters).

Now having all 3 sides of a triangle, we can determine the angle "theta".

Now that we have the angle measurement, we would add the height of the buildings (or part of the building being used for our measurement) to the R value above.

So we would have new value for the two longer sides of the triangle, and we still have the "theta" angle measurement.

We could then calculate the new length of the third side of the triangle.

We would take the difference between this new length of the 3rd side and the previous length of the 3rd side to see if it would be a noticeable or measurable difference.

Then if it should be noticeable or measurable (let's say there's a 20-yard difference), we can then analyze the cityscape photograph.

I have to go get some stuff done, but maybe someone wants to pick it up from there.

But my hunch or gut feeling based on this scale is that the difference will be too small to be able to measure based on the photograph of a cityscape.

Otherwise, I suspect that some flat earthers would have already taken this approach.

That one group in Brazil (of the "Convex Earth" video) did these measurements using precision GPS equipment accurate to within a couple centimeters, but I haven't seen their actual numbers ... and I really a suspect that we'd end up needing to have accuracy to a meter or two to see the difference.