Similarity Classification of Public Transit Stations

TL;DR

This paper addresses the challenge of accurately determining whether two public transit station identifiers refer to the same station, proposing a machine learning approach that significantly outperforms baseline methods.

Contribution

The authors develop a random forest classifier utilizing trigrams, distance, and grid position features, achieving over 99% F1 score on large datasets, improving over traditional similarity measures.

Findings

Learning-based approach achieves over 99% F1 score.

Baseline methods reach at most 94% F1 score.

Naive distance threshold method scores only 75% F1.

Abstract

We study the following problem: given two public transit station identifiers A and B, each with a label and a geographic coordinate, decide whether A and B describe the same station. For example, for "St Pancras International" at (51.5306, -0.1253) and "London St Pancras" at (51.5319, -0.1269), the answer would be "Yes". This problem frequently arises in areas where public transit data is used, for example in geographic information systems, schedule merging, route planning, or map matching. We consider several baseline methods based on geographic distance and simple string similarity measures. We also experiment with more elaborate string similarity measures and manually created normalization rules. Our experiments show that these baseline methods produce good, but not fully satisfactory results. We therefore develop an approach based on a random forest classifier which is trained on matching trigrams between two stations, their distance, and their position on an interwoven grid. All approaches are evaluated on extensive ground truth datasets we generated from OpenStreetMap (OSM) data: (1) The union of Great Britain and Ireland and (2) the union of Germany, Switzerland, and Austria. On all datasets, our learning-based approach achieves an F1 score of over 99%, while even the most elaborate baseline approach (based on TFIDF scores and the geographic distance) achieves an F1 score of at most 94%, and a naive approach of using a geographical distance threshold achieves an F1 score of only 75%. Both our training and testing datasets are publicly available.