Highway Elevation Data Smoothing Using Local Enhancement Mechanism and Butterworth Filter

Xinqiang Chen, Zhibin Li, Yinhai Wang, Chaojian Shi, Huafeng Wu, Shengzheng Wang
2017 International Journal of Innovative Computing, Information and Control  
Highway elevation is an important factor for performing quantitative and qualitative analysis of traffic safety, traffic operation and management. Google Earth provides public accessible highway elevation data which is deemed as a credible elevation source by many researchers and transportation practitioners. However, the raw elevation dataset, extracted from Google Earth, shows multiple types of outliers. Hence, we presented a local enhancement mechanism integrated with Butterworth filter to
more » ... move noises in the raw elevation data. Segment's elevation under local extrema grades was adjusted by the local enhancement mechanism before the Butterworth smoothing process. This operation helped reduce the side effect of over-smooth phenomenon for the Butterworth filter. Elevation data for three typical freeway segments, with some typical categories of outliers, has been analyzed and smoothed. The smoothing results provided evidence that the proposed smoothing model was good at reducing the noises in the raw elevation data. This research can help traffic regulators, administrative departments and field researchers construct trustable and large-scale elevation dataset for nationwide highways.
doi:10.24507/ijicic.13.06.1887 fatcat:bsqnqvph2jdtrdgzhl4nsskwae