This paper describes the use of a Geographical Information System (GIS) in Madrid, Spain, to measure the city's coverage by underground and suburban railways, and to assist the planning of public transport services. The coverage method traces circles of radii 300m, 600m and 900m around each station, and uses the GIS to calculate the numbers of people living in the areas bounded by these circles. The difficulties of this approach are indicated, together with their partial resolution. Coverage by the two rail networks was analysed in different spatial divisions, obtained from existing administrative units such as municipalities and districts. For each of the radii considered, very different degrees of coverage, ranging from less than 20% to 100%, were found for different spatial divisions. The results of this analysis could be applied to planning the location of new stations. The use of GIS in rearranging bus routes could be very useful for calculating very simple and clear indicators, to achieve objectives such as more accessible new bus routes. The GIS's coded database of Madrid's public transport network could also be useful for traffic assignment calculations.
Abstract