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
Consumption map Consumption map A consumption map or efficiency map shows the brake-specific fuel consumption in g per kWh over mean effective pressure per rotational speed of an internal combustion engine. The x-axis shows the rotational speed range. The y-axis represents the load on the engine. The contour lines show the specific fuel consumption, indicating the areas of the speed/load regime where the engine is more or less efficient. The map contains each possible condition, combining rotational speed and mean effective pressure. It shows the result of specific fuel consumption. A typical rotation power output P (linear to formula_1 ) is reached