Where could I Be ?
If I look at two landmarks (identifiable features with known coordinate) and
if I am able to measure the apparent angle between these two points, could I
derive my position from that observation ?
No, because there exist a full set of point (called a Locus of point) that
will accommodate these parameter.
Locus of point defined by a constant view angle from 2 fixed points.
Set of point defined by the fact that they form a given angle with two fixed
points (A et B, of the Euclidian Plane).

NB : Be careful to be coherent with the orientation of your
angles, and that the construction is not the same if the angle is acute (<90°)
or obtuse (>90°)