The purpose of a transit document is threefold: to mark and describe the points of interest for a transit system, to describe the paths connecting the routes, and to describe for a trip along a path the times at which each point is reached. Point definitions are split into groups based on the type of structure: train stations, which are large structures providing train service that may or may not have parking; Park & Ride lots, which are a lot (no address) providing bus service and parking, and bus stops, a point providing bus service and no parking. In Cobb county, CCT has another type of point, the bus transfer center. These act as a hub for multiple bus routes, similar to the bus bays that MARTA uses at their train stations. However, of the two transfer centers (Marietta and Cumberland), one has a parking lot, making it, in effect, a Park & Ride, and I think it's fair to simply call the other a stop. There are two basic types of route: bus and train. A train can only stop at a station. While it's true that a bus only stops at bus stops, and in a perfect world all of the bus stops would be known, transit systems (I'm looking at you, MARTA) only provide the points used for route scheduling, leaving the application writer forced to assume that a bus can stop at any point on its route. There are some routes where the bus does have an extended period where it will not stop, such as shuttles, express routes and routes using a highway, but those variations are handled in the route definitions. A path is a named portion of a line that can be used in multiple line definitions. This is helpful for when two lines overlap. To use MARTA as an example, the Proctor Creek trains run between Banhead station and (depending on the time) a station as far east as Candler Park. However, only Bankhead station is not on the east-west line. A named path between Ashby and Candler Park could be used for both the east-west line and the Proctor Creek line. As another example, the split between the North and Northeast lines happens about a mile north of Lindbergh. This shared track segment could be defined and shared using a path element. The purpose for this element is similar to that of the rail's path element, but intended more for variations in a bus's route. Bus systems often define more than one path for a particular route in order to reuse the main route's path when adding selective trips and variations, and this element provides a similar mechanism. A route can only appear in one routegroup. Like with the route definitions, the schedules are split by route type. This element defines the days used elsewhere in the document. The holidays is a list of days considered a holiday by the transit system. The station element describes a train station. It includes the stations address, county, type (for parking information) and an optional link to the transit system's web page for the station. The county is separate from the address since, though it is not used for mailing information, it is useful for understanding the taxing district in which the station exists. A link to the transit system's web page for the station. This element is optional in case the system does not provide a particular site. This element is meant to describe the type of parking available at the station. This information might be displayed on a map by using a different icon for the different types. No parking is available. 24-hour parking is available, but no overnight parking. Parking is available for periods longer than 24 hours. Park and ride lots differ from train stations in terms of data provided in that park and ride lots do not normall have an address. For this reason, the address element is replaced by a freeform location element. Everything else is pretty much the same. Bus stops, since they're normally just a point in the road somewhere, provide very little information. The name should also serve as a description of the location. This type is used by the path element in raillines. A line connects rail stations together into an ordered unit as well as providing information for the actual placement of the tracks when available. This type is used by the path element in busroutes. A route is a single line take by a bus. Routes with multiple paths should be defined as multiple route elements, using path elements to share common pieces. Bus routes, unlike rail lines, are treated as unidirectional, so the two directions of a bus route should be specified separately. Routes can be grouped into a single group using the routegroup element. A railtrip describes the times at which a train passes through particular stations. The trip does not need to include all stations on the line. The endpoints of the trip will be treated as the points where the train begins and ends. A bustrip, like a railtrip, describes the times at which a bus crosses a particular point. The difference is that a bus trip can contain more types of point. A latitude/longitude coordinate pair describes a point on the surface of the earth, a sphere for the purposes of the coordinate system. The latitude component describes the angle between the equator and a line parallel to the equator that intersects the point. The longitude component describes the angle between the prime meridian and an arc through the poles that intersects the points. As such, latitude numbers must be in the range [-90,90], and longitude numbers must be in the range (-180,180]. The latitude range in inclusive since 90 and -90 describe the north and south poles, respectively, whereas in longitude -180 and 180 are equivalent. Pathref elements are different from other point elements in that they represent a set of points instead of a single point. The pathid refers to the id of a path element within the same context (bus or rail). If this attribute is present, the points in the referenced path are reversed before being added to the current line. This enumeration describes the different types of schedule that may be available. M-F schedule