The present invention uses data from several sources to determine lines-of-sight between nodes in a FSO network. The present invention provides a three-dimensional neighborhood modeling system that uses aerial image data, Digital Elevation Models, U.S. street map data and address data to automatically map the placement of nodes within a neighborhood or other geographical area. Method for creating the 3-Dimensional, House and Tree Maps used in the line-of-sight processing are also disclosed. A House Map in the present invention identifies houses in an area of consideration, and a Tree Map in the present invention identifies trees in an area of consideration. A 3-Dimensional Map in the present invention provides an elevation for every pixel for the area under consideration, whereby the elevation is adjusted for the height of trees, houses and other objects.