Contour line factors in a weather system. An isobar (from or "baros", meaning 'weight') is a line of equal or constant pressure on a graph, plot, or map; an isopleth or contour line of pressure. More accurately, isobars are lines drawn on a map joining places of equal average atmospheric pressure reduced to sea level for a specified period of time. In meteorology, the barometric pressures shown are reduced to sea level, not the surface pressures at the map locations. The distribution of isobars is closely related to the magnitude and direction of the wind field, and can be used to predict
Transit map purpose of a transit map is to help passengers—especially those unfamiliar with the system—to take the correct routes to travel between two points; this may include having to change vehicle or mode in the course of the trip. The map uses symbols to illustrate the lines, stations and transfer points, as well as a system of geographic identification. At the same time the map must remain simple to allow overview, and be usable by those unfamiliar with the geography of the area. Stations are marked with symbols that break the line, along with their names, so they may be referred