Considering The Topological Consistency Of Line-Surface Hybrid River Network Axis Extraction

In recent years,the link between big data and the traditional GIS industry has become increasingly close and an inevitable trend..In the era of big data,a large number of multi-source and heterogeneous data using digital river network as a platform carrier play an important role in providing government departments,researchers and the public with massive data with relevant topological information,the acquisition of high-precision river networks with topological consistency can provide basic support for hydrological analysis of watersheds of different scales,.At the same time,there are more and more applications that rely on the network topology of the river network,such as watershed transportation planning,on the other hand,river network data without topological support will also greatly limit the increasing demand for intrinsic connection calculations of spatial entities in the current application environment.Therefore,it is very important to study the multi-source line-surface hybrid river network axis extraction method that takes into account the topological consistency.This paper first analyzes the traditional central axis extraction method,briefly introduces the basic principles of each extraction algorithm and its advantages and disadvantages,points out that there are few studies on multi-source heterogeneous data for line-surface mixing and algorithms that consider topology consistency.The focus of this paper is on the analysis of the data characteristics and topological consistency of the line-surface hybrid river network and how to achieve the fusion processing of multi-source heterogeneous source data.Based on the above research,this paper designs and implements two central axis extraction methods based on morphological refinement and map algebraic distance transformation.The author mainly evaluates the accuracy and computational efficiency of the proposed algorithm by the evaluation system consisting of the central axis extraction form,algorithm efficiency and river network topology connectivity.The experimental results show that the central axes extracted by the two algorithms have continuous and smooth morphological features,which better reflect the original river structure,and can also be good for the original single-line river obtained by rasterization of linear rivers,the reservation ensures the correlation between the central axis and the important tributaries of the surrounding area,and realizes the fully automatic centralaxis extraction algorithm that maintains the topological consistency,which can satisfy more spatial analysis functions.