Method for identifying closed loops to be merged in OSM urban road data

The invention discloses a method for identifying a to-be-merged closed loop in OSM urban road data. The method comprises the following steps: converting OSM urban road data in a specified area range into graph data; identifying the polylines to be combined by calculating the included angle of any two polylines on the node; calculating the number of the multi-segment lines intersected by all nodes on the to-be-combined multi-segment lines so as to identify breakpoints; identifying a connection path between the breakpoints by using a breadth-first algorithm; calculating the roundness rate of the shortest polygon to which the connection path belongs, so as to screen polylines for repairing the loop; adding the available polylines into the to-be-combined polyline combination; for the repeatedly appearing available polylines, checking whether the nodes of all polylines in the same group have breakpoints or not again; and outputting a combination of all connection paths on the closed loop. According to the method,