Approximate Nearest Neighbor Fields (ANNF) with at most d = 5 layers in depth. Every quadratic subfield stores two nearest elements from the floor plan. For example, the highlighted subfield marked with a cross stores a blue line segment as its nearest neighbor and a pink line segment as its second nearest neighbor. The data structure can be constructed up-front, and can be used as a look-up table with Od complexity. On the left, we show a performance validation as two zoom-in figures. The orange dot indicates a tested position that has the second nearest element from the ANNF as its closest element. The green dot indicates a location where the ANNF search did not include the ground truth closest element. An interactive demo can be found at here. Interactive demo