 Even if official geographical accurate maps are not available, these can often be obtained from unofficial sources since the information is available from other sources.There are a growing number of books, websites and works of art on the subject of urban rail and metro map design and use.There are now hundreds of examples of diagrams in an urban rail or metro map style that are used to represent everything from other transit networks like buses and national rail services to sewerage systems and Derbyshire public houses.