Automatic Generalization for Line Features in Risk Mapping of Natural Hazard:Taking Railway Hazard-Affected Bodies as an Example

Disaster-formative environment can magnify or shrink the vulnerability of hazard-affected body and the losses of disaster.Based on geography and cartography science,from the perspective of disaster system,the problem of linear hazard-affected body′s cartographic generalization was discussed based on layer constraints and Douglas-Peucker.Taking railways as an example,the constrained layers database was constructed,the six layers were seismic long-term intensity zoning,the risk of landslides disasters,and activity level of debris flow,mean annual maximum snow depth,flooding frequency,maximum annual day numbers of dust storms and the distribution of lakes.Combined with railway density and risk matrix of integrated hazard intensity,the automatic generalization of railway hazard-affected bodies was done in different regions and sections.The results reveal a regional rule for railway density distribution under multi-scales.