Algorithm for on-line calendar text generation in public transport

Abstract

This article describes heuristic algorithm generating calendar text for various stop timetables and for usage of third parties, i. e. governments, companies, vehicle computers, clearing centers etc. For convenience and better user experience, the calendar text does not usually contain simple list of days, but rather variations of shorter and more meaningful texts relevant to human understanding of time intervals. The goal of the algorithm is on-line distribution of trips into all published symbols (for example the pair of symbols: workdays, weekends), and conversion of differences between trips validity and each symbol validity into a short readable text. The algorithm is using standard and user defined symbols. For the given published symbol, we find for each trip the minimal number of subintervals with similar pattern. For each subinterval, we generate calendar text with positive and negative meaning and we publish the shorter one. The algorithm was developed and tested on timetables data of several Czech cities, and currently is implemented within a software for timetabling and within several public information systems of Czech transport companies.