technical

A Practical Guide to Map-Matching with Valhalla Map Matching API

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Map matching solves a fundamental problem with GPS data; Raw GPS data from vehicles or phones is inherently noisy. It zigzags through buildings, jumps across intersections, and disappears in tunnels. For any serious traffic analysis, emission modeling, or routing application, this raw data is unreliable. The solution is map-matching: the process of snapping a sequence … Read more

Estimating Traffic Speeds from GPS Trajectories: Leveraging Apache Spark for Floating Car Data (FCD) Analysis

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Analyzing large-scale floating car data (FCD) provides valuable insights into urban mobility, road usage, and traffic flow. One of the critical steps in this analysis is accurately estimating vehicle speeds from GPS trajectories—especially when turn-specific information is difficult to retrieve. In this post, I’ll walk through the process I followed to calculate and impute traffic … Read more