No, I did not find any explanation in Hipparchus javadoc, although when defining a zone on the surface of the earth, “counter clockwise manner” is mentioned couple times, that is why I assumed drawing the polygonal FoV would be similar.
In the other post, I’ve mentioned a code snipped about checking the initial footprint within the propagation:
initialCartesianOrbit = CartesianOrbit(SGP4_pv, ECI, initialDate, Mu_earth)
state = SpacecraftState(initialCartesianOrbit, satellite_mass)
inertToBody = state.getFrame().getTransformTo(earth.getBodyFrame(), state.getDate())
fovToBody = Transform(state.getDate(),
state.toTransform().getInverse(),
inertToBody)
footprint = imagerFOV1.getFootprint(fovToBody, earth, radians(10.0))
footPrintList.append(footprint)
After applying your algorithm, this bit gave me lat/long coordinates very close to what I have aimed to get at the first place… And I noticed that they were somewhat in backwards order. Then, I tried to enter the geodetic point set I have in clockwise order, and voilà! Issue is solved with trial and error, per se. 