Approximate Euclidean shortest paths in polygonal domains

Given a set $\mathcal{P}$ of $h$ pairwise disjoint simple polygonal obstacles in ${\mathbb{R}}^2$ defined with $n$ vertices, we compute a sketch $\mathrm{\Omega }$ of $\mathcal{P}$ whose size is independent of $n$, depending only on $h$ and the input parameter $ϵ$. We utilize $\mathrm{\Omega }$ to compute a $(1+ϵ)$-approximate geodesic shortest path between the two given points in $O(n + h((\lg{n}) + (\lg{h})^{1+\delta} + (\frac{1}{\epsilon}\lg{\frac{h}{\epsilon}})))$time\mathrm{.}Here,$\epsilon$ is a user parameter, and $\delta$ is a small positive constant (resulting from the time for triangulating the free space of $\mathcal{P}$ using the algorithm in \cite{journals/ijcga/Bar-YehudaC94}). Moreover, we devise a $(2+ϵ)$-approximation algorithm to answer two-point Euclidean distance queries for the case of convex polygonal obstacles.