  Imagine a polygon-shaped platform $P$ and only one static spotlight outside
$P$; which direction should the spotlight face to light most of $P$? This
problem occurs in maximising the visibility, as well as in limiting the
uncertainty in localisation problems. More formally, we define the following
maximum cover problem: "Given a convex polygon $P$ and a Field Of View (FOV)
with a given centre and inner angle $\phi$; find the direction (an angle of
rotation $\theta$) of the FOV such that the intersection between the FOV and
$P$ has the maximum area". In this paper, we provide the theoretical foundation
for the analysis of the maximum cover with a rotating field of view. The main
challenge is that the function of the area $A_{\phi}(\theta)$, with the angle
of rotation $\theta$ and the fixed inner angle $\phi$, cannot be approximated
directly. We found an alternative way to express it by various compositions of
a function $A_{\theta}(\phi)$ (with a restricted inner angle $\phi$ and a fixed
direction $\theta$). We show that $A_{\theta}(\phi)$ has an analytical solution
in the special case of a two-sector intersection and later provides a
constrictive solution for the original problem. Since the optimal solution is a
real number, we develop an algorithm that approximates the direction of the
field of view, with precision $\varepsilon$, and complexity
$\mathcal{O}(n(\log{n}+(\log{\varepsilon})/\phi))$.
