Schematic Network Map Segmentation Splicing Algorithm

Schematic Network Maps is the representation of highly abstracted graphic symbols. Its purpose is to focus on the topology structure of features and express geographic or geometric network structure in an easy understanding way. Schematic network maps has been applied in the expression of network system, such as public traffic system and pipeline network system. As the up-to-date schematic map drawing by hand or with the help of drawing software is a time consuming process, automatic generating of schematic network map is urgent and necessary. Most auto schematic algorithms are based on linear structure at present, those algorithms have only considered the local arrangement of points and lines that cannot effective schematize the entire network. Also those algorithms are have difficulty in maintaining topological consistency of the network.This paper put up a new algorithm for automatic generating of schematic network map. Our algorithm based on the subdivision and stitching of network structure. The network structure can be divided into multiple polygon graphs, an ordered set of polygons, and hanging chains, an ordered set of lines. Schematization of network is implemented by the procedure of single polygon schematization, multiple polygons combined growing model, polygon graphs attaching and hanging chains stitching. Experiments show that our algorithm can achieve the completely schematization of network and optimize network spatial distribution. Also, generated maps are clearly and easy to read. What is more, our algorithm is more efficient and good at maintaining topological consistency.Paper’s contents and conclusions are divided into the following four points:(1) Construct schematic network map layout model. With reference to the graph theory and the idea of network subdivision, this paper redefined the network structure and spatial objects. Schematic network map layout specifications are discussed and layout model that adapts to our algorithm are constructed.(2) Put forward automated schematic method for network maps based on the idea of network subdivision and stitching. Subdivision process divides network structure into polygon graphs and hanging chains while the inverse process, stitching, joins each parts together after schematization, such that completing the schematization of entire network.(3) Implement single polygon schematization. Layout satisfied polygon schematization conditions and the realization methods are given. Problems occurred in the procedure of single polygon schematization are discussed as well as solutions are given.(4) Construct polygons combining growth model. The schematization of polygon graph is achieved by polygons combining growth process. Topological constraints between polygons in the procedure are also discussed.