Columbus is a system created by Go-Jek to build their own digital map and calculate shortest paths using driver GPS location data collected every 10 seconds. The GPS data is clustered and centroids are used as nodes to create a directional graph representing the road network. Shortest paths between nodes can then be found to allocate the nearest driver to customers. Key challenges include processing the large volume of GPS data, dealing with location inaccuracies, identifying clusters, and determining the directional connections between nodes to accurately represent the road network.