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## Inputs

Observation Height h= inches feet miles millimeters meters kilometers o= inches feet miles millimeters meters kilometers as  tangent (level from observer) curve (great circle distance) R= inches feet miles millimeters meters kilometers ϕ= latitude°    Refraction(0%) * w= px fov= °

## Calculations

value formula in ft mi mm m km
Horizon * d=sqrt(h(h+2×R)) horizon horizon horizon horizon horizon horizon
Surveyor Drop Dₛ=8"×o² dropₛ dropₛ dropₛ dropₛ dropₛ dropₛ
Drop D=R/cos(o/R)-R drop drop drop drop drop drop
Obscured * x=sqrt((o-d)²+R²)-R obscured obscured obscured obscured obscured obscured

value formula radians degrees DMS
Tilt ∠ t=o/R tilt tilt tilt
Dip ∠ * a=atan(d/R) dip dip dip
Angular Size α=2*atan(h/o/2) α α α

value formula pixels
Sagitta, horizon centered w*(H*cos(a)-(Z*cos(fov/2)*sin(a))/(2*Z*sin(fov/2)) sag
Sagitta, camera level w*d/R*tan(fov/4)/2 sag

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```NOTES (v0.0.6):
Calculations assume equal elevation terrain, clear line of sight, sane input values.
```