Mapping road networks is currently both expensive and labor-intensive. High-resolution aerial imagery provides a promising avenue to automatically infer a road network. Prior work uses convolutional neural networks (CNNs) to detect which pixels belong to a road (segmentation), and then uses complex post-processing heuristics to infer graph connectivity. We show that these segmentation methods have high error rates because noisy CNN outputs are difficult to correct. We propose RoadTracer, a new method to automatically construct accurate road network maps from aerial images. RoadTracer uses an iterative search process guided by a CNN-based decision function to derive the road network graph directly from the output of the CNN. We compare our approach with a segmentation method on fifteen cities, and find that at a 5% error rate, RoadTracer correctly captures 45% more junctions across these cities.
@article{arxiv.1802.03680,
title = {RoadTracer: Automatic Extraction of Road Networks from Aerial Images},
author = {Favyen Bastani and Songtao He and Sofiane Abbar and Mohammad Alizadeh and Hari Balakrishnan and Sanjay Chawla and Sam Madden and David DeWitt},
journal= {arXiv preprint arXiv:1802.03680},
year = {2018}
}