How can we find out if a point with a certain lat and long is located on road graph?
<p>I am writing a Windows application in C# which should find the nearest path (road) between two points in the city. I needed to access the road data, like the coordinates of the beginning and end of the roads, maybe a complete database. </p>

<p>I did not know how I can access such an information or file. So for simplicity I assumed some certain vertices and the edges (the connection between the vertices). Now I have a point (coordinates of a specific location). I want to see on which edge this point is located. I see by just having information about start and end of vertices and the connection between them (edges=roads) I cannot locate a position of a point on the roads. I need to know if there is any way to find out if a point with a specific coordinates is located on a specific road. I also want to know what kind of information do usually map data contain--is it just the coordinates of two ends of roads, or more info about roads?</p>
